If you are searching for how to translate fuel economy, how to translate MPG to L/100 km, or how to preserve km/L, mpg, L/100 km, kWh/100 km and driving-range figures across languages, the first thing to understand is that these are not interchangeable labels. Some measures get larger when efficiency improves; others get smaller. A literal unit swap can therefore reverse the meaning of “better fuel economy.”
Fuel-economy translation matters in vehicle specifications, automotive websites, owner manuals, comparison tables, rental listings, road tests, fleet reports and electric-vehicle information. A target-language page can look accurate but mislead readers if US mpg and Imperial mpg are treated as the same, if L/100 km is described as “mileage,” or if an EV energy-consumption figure is confused with driving range.
This guide explains how to translate fuel economy, consumption and range without changing vehicle performance meaning. It covers miles per gallon, litres per 100 kilometres, kilometres per litre, US versus Imperial gallons, combined/city/highway cycles, EV kWh/100 km, Wh/km, energy use, fuel tank range, estimated range and how to verify conversions mathematically before publication.
Why fuel-economy translation is mathematically directional
Fuel economy is unusual because different markets express the same idea in opposite mathematical directions. In mpg or km/L, a larger number generally means more distance per unit of fuel. In L/100 km or kWh/100 km, a smaller number generally means less energy consumed per distance.
The test cycle also matters. A figure labelled “combined” is not interchangeable with city or highway consumption, and a laboratory rating is not the same thing as a real-world user result. Translation should preserve the source test context.
The gallon itself is a source of error. US and Imperial gallons differ in volume, so a numerical mpg figure cannot be converted correctly unless the source convention is known.
The safest workflow is to preserve the source figure and test label first, then add a verified target-unit conversion only when the brief calls for one.
A reliable translation method
1. Identify the source metric
Determine whether the source uses US mpg, Imperial mpg, L/100 km, km/L, kWh/100 km, Wh/km or another measure. Never infer from “mpg” alone when market context is uncertain.
2. Identify the test context
Keep city, urban, highway, extra-urban, combined, mixed, certified, estimated and real-world figures distinct. A conversion should not change the test category.
3. Preserve directionality
Remember that distance-per-fuel measures rise with better efficiency, while fuel-per-distance measures fall. Translate comparative language such as better, lower, higher and more efficient accordingly.
4. Use the correct gallon basis
If converting mpg, establish whether the source uses US gallons or Imperial gallons. The numeric conversion differs.
5. Keep range separate from economy
Range tells how far the vehicle can travel under stated assumptions; economy tells how efficiently it uses fuel or energy. Do not translate one as the other.
6. Handle EV energy metrics separately
For electric vehicles, kWh/100 km and Wh/km describe energy consumption, while battery capacity and estimated range are separate specifications.
7. Round only after conversion
Carry enough precision through the calculation and round only at the presentation stage so small errors do not accumulate.
8. Verify with an independent calculation
Check every converted figure using a second calculation or reliable conversion method, then confirm that the translated comparison still ranks vehicles in the same efficiency order.
Twenty-four recurring fuel-economy translation problems
1. US mpg
This problem appears when the source market uses US gallons. A source value such as 30 mpg (US) carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
2. Imperial mpg
This problem appears when the source market uses Imperial gallons. A source value such as 30 mpg (Imp) carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
3. L/100 km
This problem appears when the source expresses fuel consumed per fixed distance. A source value such as 6.5 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
4. km/L
This problem appears when the source expresses distance travelled per litre. A source value such as 15.4 km/L carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
5. City economy
This problem appears when a specification separates lower-speed urban driving. A source value such as City 8.2 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
6. Highway economy
This problem appears when a specification reports higher-speed road testing separately. A source value such as Highway 5.6 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
7. Combined economy
This problem appears when the source publishes a weighted combined figure. A source value such as Combined 6.7 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
8. Real-world consumption
This problem appears when a reviewer reports observed rather than certified consumption. A source value such as Observed 7.4 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
9. Fuel-economy comparison
This problem appears when two vehicles are compared in opposite-direction units. A source value such as 45 mpg versus 5.5 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
10. Average consumption
This problem appears when a trip computer reports cumulative consumption. A source value such as Average 6.2 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
11. Instantaneous consumption
This problem appears when a dashboard shows moment-to-moment use. A source value such as Instant 12 L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
12. Tank range
This problem appears when the source estimates distance from remaining fuel. A source value such as Range 620 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
13. Fuel-tank capacity
This problem appears when tank size appears next to economy figures. A source value such as 50 L tank carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
14. EV kWh/100 km
This problem appears when electric energy use is reported per 100 kilometres. A source value such as 16.8 kWh/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
15. EV Wh/km
This problem appears when the source expresses the same energy direction per kilometre. A source value such as 168 Wh/km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
16. EV estimated range
This problem appears when battery-based range is reported separately from consumption. A source value such as Estimated range 480 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
17. Hybrid economy
This problem appears when a hybrid specification combines fuel and electric information. A source value such as 4.2 L/100 km combined carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
18. Plug-in hybrid data
This problem appears when fuel and electric consumption appear in the same table. A source value such as 1.5 L/100 km + 14 kWh/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
19. Miles per litre
This problem appears when an unusual source uses mixed distance/volume units. A source value such as 12 miles/L carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
20. Gallons per 100 miles
This problem appears when fleet or engineering data reverses mpg logic. A source value such as 3.2 gal/100 mi carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
21. Cost per distance
This problem appears when the source converts fuel use into operating cost. A source value such as $8.40 per 100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
22. CO2 alongside economy
This problem appears when emissions are shown next to consumption. A source value such as 120 g CO2/km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
23. Range under conditions
This problem appears when the figure depends on temperature, load or driving cycle. A source value such as range under test conditions carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
24. Fuel economy after unit conversion
This problem appears when the target market expects another unit system. A source value such as source 40 mpg, target L/100 km carries more information than a number alone: it encodes distance, fuel or energy quantity, test condition and often a market convention. If one of those layers changes during translation, the target figure can become mathematically correct-looking but conceptually wrong.
The translator should preserve the source metric and test label first. If the target audience benefits from a converted figure, calculate it explicitly and keep the original unit visible where useful. For reciprocal systems such as mpg and L/100 km, do not use a simple linear multiplier: the relationship reverses because one measure expresses distance per fuel while the other expresses fuel per distance.
For quality assurance, identify whether a higher or lower number represents better efficiency in the source system, then check that the target wording preserves that direction. Recalculate independently, verify the correct US or Imperial gallon basis where relevant, and confirm that city, highway, combined, observed and estimated figures have not migrated between rows.
Common failure modes
1. Treating US mpg and Imperial mpg as identical
They use different gallon volumes. A conversion made without identifying the source gallon can be wrong even if the arithmetic is internally consistent.
2. Applying a simple multiplier between mpg and L/100 km
These measures are reciprocal. Better mpg means lower L/100 km, so the conversion must preserve the inverse relationship.
3. Translating “higher economy” as higher consumption
In L/100 km, better efficiency usually means a lower number. Comparative wording must follow the metric’s direction.
4. Merging city, highway and combined values
Test categories are part of the specification and should remain separate.
5. Confusing range with economy
A vehicle can have long range because of a large tank or battery even if its efficiency is ordinary.
6. Treating EV kWh/100 km as battery capacity
Consumption and stored energy are different quantities. Keep them separate.
7. Rounding before conversion
Early rounding can distort comparison tables, especially when figures are converted twice.
8. Presenting real-world observations as certified ratings
Preserve whether the source is an official test figure, manufacturer estimate or observed reviewer result.
Worked practice
Practice 1: US mpg to L/100 km
Situation: A US-market review reports 30 mpg.
Reasoning: First verify US gallons, then perform the reciprocal conversion and label the target figure as a converted value rather than rewriting the source as if it originally used metric units.
Practice 2: Imperial mpg to L/100 km
Situation: A UK source reports 50 mpg.
Reasoning: Confirm Imperial gallons before conversion; using the US factor would produce a different result.
Practice 3: Combined versus highway
Situation: A table lists 6.8 combined and 5.4 highway L/100 km.
Reasoning: Translate both labels and values separately. Do not choose the more favourable figure as the general economy number.
Practice 4: Trip-computer reading
Situation: A driver reports 7.1 L/100 km over 2,000 km.
Reasoning: Preserve this as observed average consumption rather than a certified rating.
Practice 5: EV consumption
Situation: An EV uses 17.5 kWh/100 km.
Reasoning: Keep the consumption metric separate from battery capacity and range.
Practice 6: Plug-in hybrid
Situation: A PHEV table contains both fuel and electricity consumption.
Reasoning: Translate both systems because omitting either changes the energy-use description.
Practice 7: Comparison article
Situation: Vehicle A is listed in mpg and Vehicle B in L/100 km.
Reasoning: Convert one system to the other on a common basis before making comparative statements.
Practice 8: Estimated range
Situation: A manufacturer lists 600 km estimated range.
Reasoning: Translate the estimate label and conditions; do not present it as guaranteed distance.
Calculators, vehicle sources and AI
Manufacturer specifications, official test labels and the source publication are the strongest evidence for the original metric and test cycle. Conversion tools are useful only after the source convention is identified correctly.
For reciprocal conversions, keep several decimal places during calculation and round only for display. A useful QA check is to convert the target figure back into the source unit and confirm that it returns close to the original value within rounding.
AI can explain fuel-economy systems, but it may assume US mpg or Imperial mpg from context incorrectly. State the gallon basis explicitly and verify the arithmetic independently.
How this fits the wider eduKate translation system
Fuel-economy translation combines numbers, ratios, comparison language and domain terminology. The broader method is developed in Master Art of Translation | The Complete System for Moving Meaning Between Languages. Vocabulary depth connects to the Vocabulary Learning Hub, while comparison, quantity and proportional language connect to How English Works.
FAQ
Is US mpg the same as Imperial mpg?
No. The gallon volumes differ, so the numeric values are not directly equivalent.
Is higher mpg better?
Generally yes: it means more distance per gallon.
Is higher L/100 km better?
Generally no: it means more litres consumed for the same 100 km.
Can mpg be converted with a simple multiplier?
Not to L/100 km. The relationship is reciprocal.
Should city and highway figures be averaged manually?
Not unless the methodology is specified. Preserve the source’s published combined value where available.
Is EV kWh/100 km the same as battery capacity?
No. One is energy consumption per distance; the other is stored energy.
Can range be translated as fuel economy?
No. Range and efficiency are different specifications.
Should observed fuel economy replace certified ratings?
No. Keep source categories distinct.
Can AI convert mpg accurately?
It can calculate, but you must specify US versus Imperial gallons and verify the result.
What is the simplest rule?
Preserve the source metric and test context; convert only with the correct mathematical and market basis.
Final checklist
- Have I identified the exact source fuel-economy metric?
- If mpg is used, do I know whether the source gallon is US or Imperial?
- Are city, highway and combined figures kept separate?
- Does comparative wording preserve the correct higher-is-better or lower-is-better direction?
- Are range and economy kept distinct?
- Are EV energy consumption and battery capacity kept distinct?
- Was any conversion calculated with the correct reciprocal formula?
- Was rounding delayed until the final presentation?
- Are official, estimated and observed figures labelled correctly?
- Would a target reader rank the vehicles in the same efficiency order as the source?
Fuel-economy translation succeeds when the target reader understands the same efficiency, the same test context and the same relationship between consumption and range as the source reader. Protect the original metric, identify the gallon system, keep test cycles separate and verify every reciprocal conversion mathematically before publication.