How to Learn Mortgage Refinancing Break-Even Quickly and Correctly

A lower mortgage rate sounds like an instant saving, but switching to another bank can involve legal, valuation and other charges. Mortgage refinancing break-even means the point when the financial benefit from the replacement loan has covered the costs of making the change. The correct comparison uses the outstanding mortgage balance, remaining repayment term and real rate schedules—not just the difference between the two monthly instalments. This eduKateSG Quick Notes lesson teaches a simple screening calculation, then a more accurate amortisation example so you can understand what a refinancing offer needs to prove.

Know the alternatives: stay with the current package, reprice with the current bank or refinance elsewhere.
Add switching costs: legal work, valuation, bank fees and any applicable penalty or subsidy clawback.
Start with a rough estimate: annual interest-rate difference multiplied by principal indicates the scale of possible savings.
Compare correctly: match opening principal and remaining loan term, then read actual repayment schedules.
Separate two measurements: a smaller monthly instalment is not necessarily the same as interest saved.
Check the time horizon: a future sale, rate reset or further refinancing can change the result.

Teaching paragraph 1 — identify costs before savings. Imagine a homeowner owes S$400,000 and considers moving to another bank. The new loan has a lower quoted annual interest rate, but moving may require a lawyer, a valuation and settlement of the current mortgage. Assume a fictional combined switching cost of S$3,000, paid in cash. That is an expense you incur to make the change, even if the rate is attractive. If the borrower also faces an early redemption penalty, that cost must be added. If the new bank offers a conditional legal subsidy, its genuine benefit and any future clawback should be checked. Begin with all costs of switching, not the advertised rate.

Teaching paragraph 2 — do a simple first-pass calculation. Suppose the old mortgage charges a fictional 3.2% per annum and the replacement mortgage charges 2.6%, a difference of 0.60 percentage point. Multiply that annual rate difference by S$400,000 to get approximately S$2,400 of annual interest-rate sensitivity if the full principal remained unchanged. At that crude rate, S$3,000 in switching costs might require roughly fifteen months of savings to recover. This is only a screening shortcut: a real amortising mortgage declines in principal, rates may reset, and borrowers pay different monthly amounts. Do not publish ‘fifteen months guaranteed’ from this shortcut.

Teaching paragraph 3 — learn the more accurate schedule method. Under a purely fictional model of S$400,000 outstanding, twenty years remaining, monthly amortisation, no extra payments and constant rates of 3.2% and 2.6%, the old monthly instalment is about S$2,258.65 and the new one about S$2,139.15. At twelve months, the cumulative modelled interest is approximately S$12,588 on the old rate and S$10,217 on the new, a saving of about S$2,372. That has not yet recovered the hypothetical S$3,000 fee. By month eighteen, cumulative interest saved is approximately S$3,533, exceeding the fee by about S$533 under these assumptions. A full comparison still needs the actual changing loan balances, one-off costs, rate schedules and any later contractual events. The useful principle is calculate savings over the time you will actually hold the new mortgage.

The Refinancing Break-Even Map

MoneySense’s home-loan guide explicitly recommends comparing staying, repricing and refinancing, checking the lock-in and asking the current bank about termination penalties, legal costs and clawbacks. The bank should explain how its offered package benefits you, rather than asking you to trust a headline rate.

Write every switching cost as a positive amount in one column, then list the expected interest difference separately. Do not count a cashback payment twice—once as a discount on the legal fee and again as cash income—when it represents a single economic benefit.

Old-loan balance: the principal outstanding at the proposed switch date.
Old package: its actual rate schedule and remaining repayment period.
New package: the offered all-in rates, repayment period and conditions.
One-time costs: genuine legal, valuation, administrative and penalty charges.
Relevant horizon: how long you expect to keep the new mortgage before a sale, rate reset or another change.
Break-even: the point when cumulative net economic benefit covers the switching costs.

Worked Example: Twelve, Eighteen and Twenty-Four Months

The imaginary loans start with the same S$400,000 principal and twenty years remaining. Assume the old interest rate stays at 3.2% and the new one at 2.6% for the compared period. With monthly reducing-balance amortisation, the old payment is about S$2,258.65 and the new payment about S$2,139.15. Their difference is S$119.50 of monthly cash flow, not a direct measurement of total interest savings.

After twelve payments, modelled interest on the old loan totals about S$12,588, compared with S$10,217 on the new. The new loan has saved about S$2,372 in interest but switching cost S$3,000, so this simplified comparison still has about S$628 of costs unrecovered.

After eighteen payments, the cumulative interest difference is approximately S$3,533, about S$533 greater than the S$3,000 switch fee. After twenty-four payments, the cumulative interest difference reaches about S$4,678, roughly S$1,678 more than the fee. In this exact artificial model, cumulative interest saving first exceeds S$3,000 around month sixteen. The actual refinancing break-even can differ because of rate resets, amortisation rules, time value of money and one-off costs.

These figures assume the homeowner pays the switching charges separately rather than borrowing them. If the new lender adds fees to the loan, or the borrower uses cash that could have served other financial needs, the economic comparison changes. Request real bank schedules.

Why Monthly Instalment Savings Are Not the Whole Result

In the fictional model, the monthly cash payment decreases by about S$119.50. At twelve months, that is roughly S$1,434 less paid in cash to the bank. Yet the interest difference is about S$2,372. Why? The two loans amortise at different speeds: the new loan has a lower outstanding principal as well as a lower monthly payment under the model.

Therefore a mortgage comparison should examine both the cumulative interest paid and the principal remaining at the same end date. A lower instalment may instead be achieved by extending the loan term, leaving more debt outstanding. That is why merely multiplying the monthly payment difference by twelve can be misleading.

For a household managing month-to-month expenses, cash-flow relief still matters. It is a separate benefit from total financing cost. Record both and explain which one matters most to your decision.

What Switching Costs Belong in the Calculation?

DBS’s repricing-versus-refinancing explanation notes that changing banks normally involves legal and valuation work, and its legal fee estimates distinguish loan and transaction types. The page’s figures are examples for DBS-related situations, not standard charges at every lender.

Ask your current bank for the dated redemption cost and your proposed lender for the full cost of setup. Do not assume a mortgage package with ‘no processing fee’ has no legal expenses or no loss of an existing subsidy.

Legal and conveyancing fees for the new mortgage and discharge of the old one.
Property valuation or lender processing charges, where required.
Early redemption penalties while the old mortgage remains in lock-in.
Clawback of legal subsidies, cashback or other incentives under the original agreement.
Any permitted new mortgage setup or administration charges.
Applicable direct costs of changing linked arrangements or executing the transaction.

What If the Interest Rates Change After Year One?

A floating mortgage may reset using Compounded SORA plus a spread. A fixed introductory rate may become floating after a specified period. If the old loan’s rate falls or the new loan’s rate rises, the savings from refinancing can shrink or reverse. A break-even calculation based on permanent 3.2% and 2.6% rates will then be unreliable.

To practise uncertainty, draw three scenarios: rates stay as illustrated; the replacement rate rises after its promotional period; and the old loan becomes more competitive. You do not need to forecast SORA precisely. The aim is to see whether the decision remains sensible across plausible outcomes.

The MoneySense SORA guide explains the changing benchmark. The mortgage Letter of Offer determines the actual reference series, margin, reset dates and lock-in.

What If You Sell the Property Soon?

Suppose refinancing would recover S$3,000 costs only after about sixteen months in the fictional model, but you expect to sell the property in twelve months. You may not hold the replacement loan long enough to recover the switching expense. A new lock-in can also trigger early redemption penalties on sale, making the short-period cost worse.

Before switching, compare the planned ownership horizon with the new package’s redemption terms. A homeowner planning a sale in the next few years may value repayment flexibility more than a small interest saving. A homeowner expecting to remain for many years may value lower financing cost, provided the rate and fees make sense.

A refinancing decision is therefore partly a property and household planning decision, not just a calculation of two percentages.

Repricing Versus Refinancing: Ask the Current Bank First

Repricing means changing mortgage packages at the same bank. It often avoids some conveyancing or valuation work required for a lender switch but may involve an administration fee and a new commitment period. Refinancing means taking a replacement mortgage from another bank and settling the old lender.

MoneySense recommends checking the existing bank’s repricing options before evaluating a new lender. Ask for written quotes with the same principal and remaining term, plus clear information on fees and later-year rates. The current bank could be more competitive after costs even if the new bank advertises a lower initial rate.

Do not confuse the period needed to process a bank application with the financial break-even time. One measures administrative completion; the other measures when monetary benefits overtake costs.

The Seven-Step Break-Even Checklist

The bank’s property loan fact sheet includes key loan features, total repayment information, interest and penalty clauses. MoneySense says banks must provide it before the loan is signed. Use that document and the accepted offer rather than an advertisement alone.

Get an up-to-date outstanding principal and remaining tenure from the current lender.
Identify the old package’s rate schedule and lock-in or subsidy clawback dates.
Ask the new bank for a written offered rate schedule and property loan fact sheet.
Obtain the actual legal, valuation, redemption and other switching costs.
Compare repayment schedules for the same starting principal and remaining term.
Check cumulative interest and remaining balance at twelve, twenty-four and later months.
Evaluate sale plans, rate changes, emergency cash and potential new lock-ins before deciding.

A Ten-Minute Break-Even Lesson

Minutes 1–2: define the break-even point and list three switching costs.
Minutes 3–4: calculate the rough annual 0.60-percentage-point difference on S$400,000.
Minutes 5–6: compare that estimate with a fictional S$3,000 refinancing cost.
Minutes 7–8: learn why S$119.50 less per month is not identical to the interest saving.
Minute 9: identify one condition that could change the break-even date.
Minute 10: explain why a proper comparison includes remaining principal at the same end date.

Check Your Understanding

Question 1: How much is 0.60% of S$400,000? Answer: S$2,400, as a simple annual interest-difference proxy on a constant balance.

Question 2: Does a lower monthly instalment always prove lower total financing cost? Answer: No. Tenure and principal repayment may differ.

Question 3: Do legal and valuation costs count in refinancing break-even? Answer: Yes, if genuinely incurred.

Question 4: Can a planned home sale before break-even change the decision? Answer: Yes, because there may be insufficient time to recover switching costs.

Question 5: Is the illustrative month-sixteen break-even a guaranteed Singapore bank outcome? Answer: No. It applies only to the invented constant-rate model.

Common Mistakes to Correct

Assuming the interest-rate difference alone determines the benefit.
Leaving out an early redemption fee or legal-subsidy clawback.
Using a different term for the old and new schedules, then calling lower payments interest savings.
Comparing only the first advertised year of a long mortgage.
Assuming all fees will be waived without checking subsidy eligibility.
Forgetting that a new lock-in could constrain a planned sale.
Using the crude rate-times-principal shortcut as an exact break-even prediction.

Primary Sources and Final Rule

Official and bank sources: MoneySense: How Home Loans Work, DBS: Refinancing Versus Repricing, DBS: Estimated Legal Fees and MoneySense: SORA. These examples are mathematical teaching models and are not mortgage quotations or personalised advice. Final rule: compare like-for-like interest over your real holding period, then subtract every switching cost.