TDSR Explained with Worked Examples in Singapore

In my years helping Singapore homeowners, I’ve found that TDSR is one of the most misunderstood rules in home financing — yet it is also one of the most important. If you are buying a flat, condo, EC, or refinancing a property loan, understanding how TDSR works can save you from choosing a home that feels affordable on paper but stretches your monthly cash flow too far. In this guide, I’ll break down TDSR in plain English, show you how calculating TDSR works step by step, and walk through worked examples using Singapore-specific rules. If you want to test your numbers as you read, you can also use our TDSR tool anytime.

What TDSR means in Singapore

TDSR stands for Total Debt Servicing Ratio. In Singapore, it is the rule banks use to make sure your total monthly debt obligations do not exceed 55% of your gross monthly income. That means all your recurring debt commitments — not just your home loan — are counted together. This includes your mortgage, car loan, personal loan, credit card minimum payment, and any other ongoing monthly borrowings.

For most buyers, the key point is this: even if you have enough cash for a downpayment, your loan approval still depends on how much debt you already carry. That is why the answer to “how much can I borrow?” is not based only on property price, but on your overall debt load, income, loan tenure, and interest rate stress test.

It is also important to distinguish TDSR from MSR. MSR applies to HDB flats and Executive Condominiums financed by bank loans, and it caps mortgage repayments at 30% of gross monthly income. TDSR still applies on top of that. So for HDB and EC buyers, the stricter rule can effectively be MSR, while for private property buyers, TDSR is usually the main affordability constraint.

If you want to compare your borrowing power across loan types, you may find our HDB loan calculator useful as a starting point.

TDSR Singapore rules you should know

In tdsr singapore calculations, banks use a few standard assumptions that affect the final amount you can borrow:

• The cap is 55% of gross monthly income for total debt obligations
• Variable income is often averaged using bank-approved methods
• Existing debts are included in the calculation
• Mortgages are stress-tested at a higher interest rate than the headline package rate
• Foreign currencies and certain liabilities may be treated conservatively

For the regulatory basis of TDSR and broader lending standards, I always recommend buyers refer to the Monetary Authority of Singapore as the primary authority.

A common mistake I see is buyers assuming that a low advertised rate automatically means they can borrow more. In reality, banks do not use the teaser rate for affordability checks. They apply a buffer rate for prudence, which reduces the maximum loan quantum compared with what many buyers expect.

This is why a tdsr calculator is so helpful. It lets you estimate your maximum mortgage payment allowance before you commit to a property. It is not a replacement for a bank’s final assessment, but it is a very practical first filter.

How calculating TDSR works step by step

When I’m calculating tdsr for clients, I use a simple framework:

Step 1: Add up your gross monthly income

Use your monthly salary before CPF deductions. If you have a co-borrower, combine both incomes. If income is variable, banks may average it over time or apply discounts depending on the source.

Step 2: Determine 55% of that amount

This is your maximum total debt repayment ceiling.

Step 3: List all existing monthly debt obligations

Typical debts include:

• Car loan instalments
• Renovation loans
• Personal loans
• Student loans
• Credit card minimum payments
• Existing property loan instalments

Step 4: Subtract those debts from the 55% ceiling

What remains is the amount available for your new mortgage instalment.

Step 5: Convert the remaining instalment capacity into a loan amount

Banks will then apply the relevant loan tenor, stress-tested interest rate, and property type rules to determine the final loan quantum.

This is exactly where many buyers underestimate the effect of debt. Even a modest car loan can reduce your property budget meaningfully.

Worked example: TDSR for a Singapore private property buyer

Let me show you a realistic example.

Scenario

• Buyer’s gross monthly income: S$10,000
• Car loan: S$600/month
• Credit card minimum payment: S$150/month
• No other debts

Step 1: Calculate 55% of gross income

55% of S$10,000 = S$5,500

That means the buyer’s total monthly debt obligations cannot exceed S$5,500.

Step 2: Deduct existing debts

Car loan: S$600 Credit card minimum payment: S$150

Total existing debts = S$750

Step 3: Find available mortgage capacity

S$5,500 - S$750 = S$4,750

So the buyer’s new mortgage instalment must fit within about S$4,750 per month.

Step 4: Translate that into loan size

If the bank stress-tests the mortgage at a higher rate and the buyer chooses a 30-year tenure, the loan quantum will depend on the exact rate assumptions. In practical terms, a monthly payment capacity of S$4,750 may support a fairly substantial loan, but not necessarily enough for every prime condo.

If the buyer has no car loan, the allowable mortgage payment would rise to S$5,350, which can make a meaningful difference in affordability.

This is why I often remind clients that the best way to think about TDSR is not just “am I below 55%?” but “how much purchasing power is my debt profile taking away?”

Worked example: how TDSR affects an HDB or EC buyer

For HDB and EC purchases, MSR is usually the tighter limit than TDSR. But TDSR still matters because your other debts can reduce what is left for the mortgage.

Scenario

• Gross monthly household income: S$8,000
• Existing car loan: S$700/month
• No other debts

MSR check

30% of S$8,000 = S$2,400 maximum mortgage payment for the HDB/EC loan component.

TDSR check

55% of S$8,000 = S$4,400 total debt ceiling.

After car loan: S$4,400 - S$700 = S$3,700 available for all mortgage debt.

In this case, MSR limits the housing instalment to S$2,400, which is below the remaining TDSR capacity of S$3,700. So the buyer passes both tests, but MSR is the binding constraint.

If you’re preparing for a new flat, it also helps to plan around cash and CPF timing. Our BTO down payment page can help you estimate what you need upfront, while the monthly installment calculator helps you map payments to affordability.

What banks include in your debt calculation

A question I hear often is: “Does TDSR only count my housing loan?” The answer is no. Banks look at your total monthly commitments, and that is the whole point of the rule.

Common items included are:

• Mortgage instalments for any property loan
• Car financing
• Renovation loans
• Personal loans
• Education loans with fixed repayments
• Minimum credit card payments

Some buyers are surprised that a small credit card balance can matter. Even if you pay your cards on time, the bank will still typically count a minimum payment amount into your monthly commitments.

On the other hand, not every expense is treated as debt. Regular living expenses are not part of the formula. But if you have structured borrowing, banks will almost always count it.

This is why I encourage buyers to clean up debt before applying if possible. Paying down a car loan or consolidating short-term liabilities can improve your borrowing headroom more than many people expect.

CPF OA usage, loan limits, and why affordability is more than TDSR

TDSR is only one part of the home-buying picture. CPF usage, loan-to-value limits, and property type rules all affect how much cash you need and how much you can borrow.

For CPF Ordinary Account usage, the general principle is that you can use CPF for housing within the rules set by the CPF Board, subject to property ownership and withdrawal limits. I always tell clients to check CPF usage carefully before committing, because the amount you can tap from CPF can affect both monthly cash flow and upfront payment planning. For the official rules, I refer clients to the CPF Board.

Loan-to-value limits also matter:

• HDB loans generally allow up to 80% LTV subject to eligibility
• Bank loans generally allow up to 75% LTV for first mortgage under standard conditions
• The exact limit can be lower depending on tenure, age, and outstanding loans

So even if TDSR says you can service a larger loan, the LTV limit may still cap your maximum borrowing. In other words, your true affordability is the intersection of TDSR, LTV, and available downpayment.

If you’re comparing options, I suggest reading our related guide on Singapore Mortgage DTI: What Banks Look At, because debt servicing concepts often get mixed up.

My practical advice before you apply

When clients ask me how to improve their chances of approval, I usually give three simple steps:

1. Reduce non-essential monthly debt before applying
2. Check your purchase budget using a proper affordability tool, not just a rough guess
3. Leave a buffer so your finances still feel comfortable after completion

I also suggest running different scenarios. For example, test the effect of removing a car loan, shortening the tenure, or changing the property type. A few hundred dollars in monthly debt can change your budget enough to shift you from one district or flat type to another.

If you are unsure whether you should buy first, refinance later, or wait until your debt profile improves, the safest move is to model the numbers early rather than after you’ve found the perfect property.

Final thoughts: use TDSR as a planning tool, not just a bank rule

TDSR is more than a compliance threshold. In Singapore, it is one of the most practical tools for keeping home ownership sustainable. Once you understand it, you can make smarter decisions about your property budget, your debts, and your timing.

If you remember nothing else from this article, remember this: your home loan does not exist in isolation. Your car loan, credit cards, and other debts all shape what you can borrow.

If you want to estimate your own numbers quickly, start with our TDSR page, then compare the result with the monthly installment calculator. If you’re planning a wider purchase budget, the homepage affordability tools at mortgageagent.sg can help you map out the full picture before you apply.

— Maeve Tan, Singapore Mortgage Specialist