A 1-Point Mortgage Rise Adds S$558 a Month to a S$1m Loan

A household borrowing S$1 million over 30 years would pay about S$4,216 a month at 3% interest. At 4%, the instalment becomes roughly S$4,774—an extra S$558 every month, or about S$6,700 a year.

That indicative calculation explains why renting can sometimes be the more useful bridge for an HDB owner considering a private home. It does not settle the choice: the answer also depends on whether you can buy yet, how much your HDB sale actually releases, the stamp duties due and how long you expect to stay.

Start with a 4% stress test

The figures above use the standard formula for a fully amortising home loan, where every monthly payment covers interest and repays part of the principal. They are planning estimates—not a bank quotation, property valuation or loan-eligibility decision.

A 4% scenario is a sensible starting point because the Monetary Authority of Singapore’s housing-loan safeguards include an interest-rate floor used when assessing affordability. The Total Debt Servicing Ratio, or TDSR, generally limits all monthly debt obligations to 55% of gross monthly income.[S1]

Do not compare only the advertised mortgage rate with the monthly rent. Run at least three loan scenarios using the amount you would really borrow—for example, 3%, 4% and 5%—and include the intended loan tenure.

For the illustrative S$1 million, 30-year loan, a further rise from 4% to 5% would lift the estimated repayment to about S$5,368 a month. That is around S$1,152 more than at 3%. A shorter loan would require higher monthly payments, although it would usually reduce total interest over the full tenure.

Renting may therefore buy something more valuable than temporary accommodation: time to see whether the higher repayment remains comfortable after ordinary expenses, childcare, insurance and other debts. But rent is still a cost, so the useful comparison is between two complete household budgets—not between rent and one mortgage instalment.

Your MOP decides whether buying is even an option

Before calculating returns or touring condominiums, check whether your Minimum Occupation Period has ended. The MOP is the period during which an HDB owner must occupy the flat and is generally not allowed to acquire an interest in private residential property.[S2]

For flats under the new classification framework, Standard flats have a five-year MOP, while Plus and Prime flats carry a 10-year MOP and tighter resale conditions.[S3] The conditions attached to your actual flat matter, so check your HDB records rather than assuming the rule from its location or appearance.

Completing the MOP does not automatically make every route workable. If you intend to retain the HDB flat while buying private property, your household’s citizenship status and HDB’s occupation rules can affect what must happen next.[S2]

This is where renting first may solve a timing problem. A household could remain in its HDB flat while building a larger buffer, or sell and rent while waiting for the right private home. Those are materially different choices: the second gives up the existing flat and exposes the household to rental costs and another move.

Your HDB sale price is not your next down payment

Suppose your flat sells for S$700,000. That does not mean S$700,000 is available for the private purchase.

CPF explains that property-sale proceeds are applied first to the outstanding housing loan, followed by the required CPF refund and then sale expenses. The CPF refund generally includes the principal withdrawn for the property and the accrued interest that money would have earned if it had remained in the account.[S4]

A more useful planning equation is:

Sale price − outstanding loan − required CPF refund − sale expenses = cash proceeds

The refunded CPF savings may potentially be used for another eligible home purchase, subject to CPF’s housing rules. They are not the same as cash in your bank account.[S4]

Ask your bank for the outstanding loan amount and check your CPF property figures before setting a private-home budget. Also allow for legal fees, agent commission where applicable, moving expenses and any overlap between the old and new homes.

Move timing deserves its own buffer. Completion dates may not line up neatly, and a temporary extension of stay is not something a seller should simply assume. If renting is the bridge, budget for the deposit, advance rent, movers and the possibility of renewing the lease.

Stamp duty can change the comparison sharply

A buyer of residential property must budget for Buyer’s Stamp Duty, or BSD. It is calculated using the higher of the property’s purchase price or market value, with progressively higher rates applying across value bands.[S5]

Additional Buyer’s Stamp Duty, or ABSD, may also apply. The amount depends on factors including the buyer’s citizenship or residency status and how many residential properties that person owns at the time of acquisition.[S6]

This makes transaction order important. Buying a private home before disposing of an existing flat can produce a different upfront tax position from selling first, depending on the household’s circumstances and any relief conditions. Obtain advice based on the actual owners and intended dates before exercising an option to purchase.

Ownership also brings recurring costs that rent does not fully mirror: property tax, maintenance charges, insurance and repairs. Renting has its own risks, including rent increases, lease-renewal uncertainty and restrictions imposed by a landlord. Put both sets of costs into the same time period—preferably at least three to five years—rather than comparing just the first month.

Keep the fallback route in view

Selling the HDB flat and buying private property can narrow your future options. If the private-home plan changes and you later return to the HDB resale market, CPF usage depends partly on the flat’s remaining lease.

CPF says the lease generally needs to cover the youngest owner using CPF to at least age 95 for the maximum applicable housing usage. If it does not, CPF usage is pro-rated; a property with a remaining lease below 20 years cannot be financed with CPF savings.[S7]

That matters if renting is meant to be temporary while you search for another HDB flat. A cheaper older flat may require more cash than expected, particularly if its lease does not cover the youngest buyer to age 95.

The cleanest decision is therefore not “rent or buy?” in isolation. It is: What flexibility does renting purchase, and is that flexibility worth its total cost?

For one household, an extra S$558 a month may be manageable and buying may provide the stability they want. For another, the same increase could remove the emergency buffer that makes ownership comfortable. Run the higher-rate repayment, establish your real post-sale cash and CPF position, confirm the HDB rules attached to your flat, and price the complete move before making an irreversible choice.