How to Calculate TDSR for a Home Loan in Singapore

TDSR is an affordability check, not just a banking acronym. It looks at whether the buyer can carry the new mortgage together with existing monthly debt commitments.

That matters on the ground because buyers often focus on income and downpayment, while banks focus on debt burden. A client may earn well and still have limited loan room once car instalments, personal loans, renovation loans, or revolving card balances are factored in.

The practical agent takeaway is this: TDSR is often the rule that quietly resets the client's budget. A buyer may shortlist a unit based on headline salary, but financing may point to a lower price range once total debt is counted.

MAS explains the framework in its MSR and TDSR rules explainer. If you need the bigger financing picture, pair this with our pillar guide on Singapore property loan rules: TDSR, MSR and LTV explained.

Useful client line: "TDSR asks how much of your gross monthly income is already spoken for by debt."

The core formula is simple:

TDSR = total monthly debt obligations ÷ gross monthly income × 100

For agents, the important point is what goes into the numerator. It is not just the new home loan. It is the new home loan plus the buyer's other recurring monthly debt repayments.

A simplified example:

• Gross monthly income: $10,000
• Existing monthly debt repayments: $2,000
• Estimated new mortgage instalment: $3,000
• Total monthly debt obligations: $5,000
• TDSR: 50%

That example is only a rough screen, not a loan approval. Banks may assess the mortgage instalment using more conservative assumptions than the advertised package rate. If you want to understand that difference, see our guide on what stress test interest rate banks use for TDSR.

As of Dec 2021, the source material summarises the common TDSR cap for property loans at 55% of gross monthly income. Treat that as a dated reference point and confirm the current figure with MAS or the lender before advising a client.

Insight line: "The mortgage is not tested on its own. It is tested on top of everything else the buyer already owes.". For a broader overview, see How Banks Assess Income for a Home Loan in Singapore.

This is one of the most common client mistakes. Buyers often quote the amount credited into their bank account, but TDSR starts from gross income before deductions such as CPF and income tax.

Fixed salary is usually the easiest part of the file to assess. Other income types, such as commission, bonus, rental income, or self-employment income, may still be considered, but banks do not always treat them the same way. That is why two buyers with similar headline income can end up with different assessed borrowing power.

For agents, the practical move is to ask early how the client's income is structured:

• Mostly fixed salary
• Part salary, part commission
• Self-employed or business income
• Rental income supporting the application

That quick classification tells you whether the case is straightforward or whether you should push for an early bank check. Common supporting documents in practice include payslips, CPF contribution history, IRAS/NOA records, bank statements, and tenancy documents, depending on the income type. For a deeper breakdown, see our guide on how banks assess income for a home loan in Singapore and DBS's overview of what to know about TDSR.

Insight line: "Gross income is the starting point. Documented, usable income is what the bank finally works with.". For a broader overview, see What Is In-Principle Approval (IPA) for a Home Loan in Singapore?.

A practical way to screen this is: if it creates a recurring monthly repayment, assume it may affect TDSR until the bank confirms otherwise.

The items buyers often forget are the ones that create bad surprises later: guarantor commitments, maintenance or alimony obligations, and other recurring credit facilities. You should not assume every lender treats every obligation identically, but you should ask about them early whenever a client says they are "basically debt-free."

Useful agent habit: ask for a plain-English debt list, not just "any loans?" Buyers are more likely to remember specifics when you ask, "Any car instalment, renovation loan, student loan, or card balance being repaid monthly?". For a broader overview, see TDSR vs MSR: What's the Difference?.

A quick TDSR check does not need to be perfect. It needs to catch obvious overreach before the client anchors on a price they may not be able to finance.

Use this four-step workflow:

1. Start with gross monthly income, not net pay.
2. List every recurring monthly debt the buyer still has to service.
3. Estimate the likely mortgage instalment for the target purchase.
4. Add the debts together and compare the total against the applicable TDSR limit.

A simplified screening example helps. If a buyer earns $12,000 gross a month, and the source material's Dec 2021 reference cap of 55% is used, total monthly debt room would be about $6,600. If the buyer already has $2,500 of other monthly debt repayments, only about $4,100 remains for the assessed mortgage instalment. Confirm the current cap and the lender's assessment basis before using that figure in client advice.

If the rough total is already near the limit, treat the case as stretched. The practical next moves are usually to:

• reduce the target purchase price
• increase the cash downpayment if feasible
• or get an IPA/AIP before making a firm offer

Insight line: "Do the financing screen before the property shortlist becomes emotional.". For a broader overview, see What Stress Test Interest Rate Do Banks Use for TDSR?.

Most bad TDSR estimates come from the same predictable errors.

Common mistakes to watch for:

• Using take-home pay instead of gross monthly income.
• Leaving out car loans, personal loans, renovation loans, student loans, or card repayments.
• Assuming all commission, bonus, rental, or self-employment income will be counted the same way as fixed salary.
• Forgetting less obvious obligations such as guarantor commitments or maintenance payments.
• Quoting a "safe budget" based only on TDSR without checking downpayment, completion costs, and real monthly cash flow.
• Treating an online calculator result as guaranteed approval.

The last mistake is the most dangerous in practice. A buyer can look fine on a rough calculator and still be cut back later because the lender applies conservative instalment assumptions or recognises income differently once documents are reviewed.

Useful agent rule: if the case is borderline, stop estimating and start verifying.

The best client explanation sounds like budgeting, not banking jargon. A clear script is:

"TDSR is the bank's check on whether your total monthly debt payments, including the new home loan, are still manageable based on your gross monthly income."

If the buyer is overconfident, use this version:

"Your salary is only one part of the picture. The bank also counts your other monthly commitments before deciding how much loan room is left."

If the buyer is anxious, use this version:

"This is not a rejection label. It is an early affordability check so we don't waste time on homes that stretch the budget too far."

Good explanation reduces resistance. Buyers usually accept TDSR more easily when they understand it as a planning tool, not a mysterious bank hurdle.

For serious buyers, an AIP or IPA is often the safer move before a firm offer. It helps you test the financing story before negotiation, option timelines, and client expectations become harder to unwind.

It is especially useful when the buyer:

• is close to the likely TDSR limit
• has recent job changes
• relies on commission, bonus, rental, or self-employment income
• has existing debts that may be under-disclosed or misunderstood

An IPA is still not final approval, but it is materially more useful than relying on a rough calculator alone. If you are guiding a buyer through the process, pair this with our guide on what is in-principle approval (IPA) for a home loan in Singapore?.

For a quick market sanity check, you can compare rough results against the PropertyGuru TDSR calculator or MoneySmart's TDSR calculator, then verify the case directly with the lender.