What is a tariff? A tariff is a customs duty charged on goods when they cross a border, most commonly when they are imported. It is usually collected by the importing country’s government and can increase the landed cost of a product. Governments may use tariffs to raise revenue, protect selected domestic industries, respond to trade-policy objectives or negotiate market access.
A tariff is not the same as every tax connected with buying or importing goods. A customs duty is a tariff or duty applied under a customs schedule. A goods and services tax (GST) or value-added tax (VAT) is a consumption tax. A product can be subject to a customs duty and GST, GST only, or a relief or exemption under the applicable country’s rules. The exact treatment depends on the product, origin, customs classification and import arrangement.
Quick notes: An ad valorem tariff is a percentage of the customs value. A specific tariff is a fixed amount per unit, weight or quantity. A compound tariff combines both methods. Tariff rates often depend on the product’s Harmonized System (HS) classification and country of origin. In Singapore, customs and excise duties apply to selected categories of goods; imported goods are generally also subject to GST under the prevailing rules, with specific reliefs and exceptions.
How a tariff works
Suppose a business imports a machine with a customs value of S$10,000. If the tariff rate for the correctly classified product is 5%, the duty in this simplified example is S$500. The importer’s cost base may therefore include the customs value, duty, freight, insurance, handling, GST and other charges, depending on the country’s valuation and tax rules.
Simplified ad valorem duty:
Customs duty = customs value × tariff rate
Example:
S$10,000 × 5% = S$500The example explains the arithmetic, not a real tariff rate for a particular machine. Actual customs valuation, the HS code, origin rules and applicable schedule must be checked before importing. A product description on an online shop is not enough to establish its customs classification.
The three common tariff methods
1. Ad valorem tariff
An ad valorem tariff is calculated as a percentage of the customs value. For example, a 10% tariff on goods valued at S$2,000 would produce a duty of S$200, assuming that the stated customs value is the correct taxable base and no other rule changes the calculation.
2. Specific tariff
A specific tariff charges a fixed amount per unit, such as a set amount per kilogram, litre or item. The duty depends on quantity rather than directly on the price of the goods. This can make the percentage burden different for low-priced and high-priced versions of a product.
3. Compound tariff
A compound tariff combines a percentage charge with a specific charge. For example, a customs schedule might apply a percentage of value plus a fixed amount per kilogram. The exact formula is defined by the tariff schedule.
What determines the tariff rate?
The rate depends on the importing country’s tariff schedule and the classification of the goods. Customs systems use the Harmonized System (HS), an internationally coordinated product-classification framework, with countries adding further digits and national detail. The code matters because products that look similar in ordinary language can be classified differently for customs purposes.
- Product classification: identify the correct HS code based on the goods’ material, function, composition and other classification rules.
- Country of origin: origin is not always the same as the country from which the parcel was shipped. Rules of origin determine where goods are considered to originate.
- Trade agreements: a free-trade agreement may provide a preferential rate if the product satisfies the rules and the importer meets documentation requirements.
- Customs value: the value used to calculate a duty is determined by the importing country’s valuation rules.
- Tariff quota or trade measures: some products may be subject to quotas, safeguards, anti-dumping duties or other measures.
A preferential tariff is not automatic just because a seller states that an item was shipped from a trade-agreement partner. The goods must meet the relevant origin rules, and the importer may need valid proof of origin and the correct declaration.
Why governments impose tariffs
Government revenue
Tariffs can raise revenue on imported goods. The importance of this role varies by country and by the structure of its tax system. Customs collection can also be administratively convenient because goods pass through identifiable border processes.
Protection for domestic producers
A tariff increases the cost of affected imports relative to comparable domestic goods, which can give local producers a price advantage. The policy may support selected industries or employment, but it can also make inputs and finished products more expensive for households and businesses.
Trade policy and negotiation
Governments can use tariff commitments and reductions in trade negotiations. Tariffs may be part of a wider package that includes market-access rules, standards, subsidies, investment and other trade measures. Retaliatory tariff increases can create trade disputes and uncertainty for companies.
Who pays a tariff, and who bears the cost?
The importer of record is generally responsible for paying the duty to customs, according to the import rules. But the economic cost can be shared across several parties. An importer may pass some of the cost to customers through higher prices, negotiate lower prices with a supplier, absorb it through a smaller profit margin or change its sourcing. The final effect depends on competition, contracts, demand and supply alternatives.
This is why a tariff’s legal payer and its economic burden are not always the same. A customs invoice identifies who must pay the government; market behaviour helps determine who ultimately feels the cost.
Tariffs versus GST, VAT and excise duty
Tariff or customs duty is a duty applied to goods under a customs schedule. GST or VAT is a consumption tax charged on taxable supplies and, subject to the country’s rules, imports. Excise duty is a tax on selected goods, often because of the product type or policy objective. A single import can face more than one of these charges.
In Singapore, Customs explains that the four broad categories of dutiable goods are intoxicating liquors, tobacco products, motor vehicles and petroleum products. Goods outside the dutiable categories are generally non-dutiable, but import GST can still apply. Therefore, ‘no customs duty’ does not necessarily mean ‘no tax at import’.
How Singapore calculates import GST
Singapore Customs states that GST on imported goods is calculated using the customs value plus duties, or in specified circumstances the last selling price plus duties. The exact calculation depends on the import transaction and permit declaration. For dutiable goods, the duty is included in the base used to calculate GST.
For example, a simplified non-dutiable import with a customs value of S$1,000 would have import GST calculated at the prevailing rate on that value, assuming no special relief or adjustment applies. For dutiable goods, the taxable base may include both the customs value and duties. Always use current Singapore Customs instructions and the correct import documents; this illustration is not a customs assessment.
Read the official guidance at Singapore Customs: Goods and Services Tax and the Import Procedures Overview.
How tariffs affect businesses and consumers
- Importers: face additional cost, classification and documentation work, and possible delays if declarations are incomplete.
- Manufacturers: may pay more for imported raw materials, components or equipment, which can affect production costs.
- Retailers: may need to adjust prices, suppliers, product ranges or inventory planning.
- Consumers: may pay higher prices for affected goods, although the final change depends on competition and how much of the duty is passed through.
- Exporters: may face lower demand in a market where their goods become more expensive, or may benefit if their own country negotiates improved access elsewhere.
The impact varies by industry. A tariff on imported steel may affect manufacturers that use steel even if they do not import the final product. A tariff on a finished consumer good may affect retailers more directly. Supply chains can also shift as firms seek alternative suppliers or locations.
Tariffs and free-trade agreements
A free-trade agreement can reduce or remove tariffs on qualifying goods traded between participating countries. It does not mean that every product from those countries automatically becomes duty-free. The agreement sets rules of origin, product-specific requirements, proof procedures and other conditions.
Businesses should confirm the product’s HS code, applicable agreement, origin criteria, supporting documents and declaration procedure. A mistake can lead to a rejected preferential claim, additional duty, penalties or delays. Customs brokers can help, but the importer remains responsible for accurate information under the relevant rules.
Common tariff misunderstandings
- ‘A tariff is the same as GST.’ Customs duty and consumption tax are separate charges with different purposes and calculation rules.
- ‘The exporter always pays the import tariff.’ The importer is generally liable to customs, although costs may be reflected in prices and contracts.
- ‘The shipping country determines origin.’ Origin is determined under rules of origin, not simply the departure port.
- ‘A free-trade agreement makes every import duty-free.’ Preferential rates apply only when product and origin rules are met.
- ‘No duty means no import tax.’ GST, VAT or other import charges may still apply.
Frequently asked questions about tariffs
What is a tariff in simple words?
A tariff is a customs duty charged on goods crossing a border, most commonly on imports.
What is an ad valorem tariff?
It is a tariff calculated as a percentage of the customs value of the goods.
Who pays an import tariff?
The importer is generally responsible for paying the customs duty, but the economic cost may be shared through prices, supplier terms and business margins.
Are tariffs and taxes the same?
A tariff is one type of tax or duty on goods crossing a border. Import GST or VAT and excise duty are different charges.
Does Singapore charge customs duty on every import?
No. Singapore Customs identifies selected categories of dutiable goods. Import GST generally applies more broadly, subject to the rules, reliefs and exceptions.
How do I find the tariff for a product?
Identify the correct HS classification, determine the country of origin, check the importing country’s tariff schedule and verify whether a trade agreement or other measure applies.
Continue learning at eduKateSG
For Singapore import procedures, continue with Customs GST, Import Relief and Duty-Free Concessions and Overseas Online Shopping, Parcel GST and Customs Duty. For a school-friendly explanation of trade barriers, read How to Learn Tariffs and Trade Barriers.
Sources and further reading
The World Trade Organization: Tariffs explains customs duties on merchandise imports and the role of tariff commitments. The WTO glossary distinguishes ad valorem and specific duties. For Singapore, consult Singapore Customs: Duties and Dutiable Goods and GST on Imported Goods. This guide is educational; importers should confirm current rates, classifications and permit requirements before shipping goods.