Buyers usually only think about the downpayment. The number that actually determines your maximum loan is a pair of ratios most people have never calculated for themselves.
The MSR cap
Mortgage Servicing Ratio applies specifically to HDB flats and Executive Condominiums, and it is the tighter of the two caps for most buyers. It limits your housing instalment alone, not your total debt, to 30% of gross monthly income, on top of the general TDSR ceiling.
The TDSR cap
Total Debt Servicing Ratio caps all your monthly debt obligations, the new mortgage instalment plus any car loan, credit card minimum, or other loan, at 55% of gross monthly income. Where you have no other debt, MSR is usually the binding constraint on an HDB purchase since it is the lower of the two percentages.
Loan to Value limits by flat type
An HDB concessionary loan runs up to 80% of the flat's value on a resale purchase, or up to 90% on a new BTO or SBF flat. A bank loan caps at 75% regardless of flat type, with a higher minimum cash component. Whichever loan type you use, the actual quantum offered is the lower of the LTV based ceiling and the MSR/TDSR based ceiling.
Worked example
On $8,000 gross monthly income with no other debt, MSR allows up to $2,400 a month toward the HDB flat instalment (30% of $8,000). At the HDB concessionary rate of 2.6% per annum over a 25 year tenure, that services a loan quantum in the region of $530,000, illustrative only; your actual offer depends on your CPF position, age, and the flat type you are buying.
Frequently asked questions
Does MSR apply if I use a bank loan for my HDB flat instead of the HDB loan?
Yes. MSR applies to any loan, HDB or bank, used to finance an HDB flat or Executive Condominium purchase. It only stops applying once you move to a private condominium or landed purchase, which is assessed under TDSR alone.
Why is my approved HDB loan lower than I expected?
Usually because MSR, not TDSR, is the binding cap: it limits the housing instalment alone to 30% of income, which is tighter than the general 55% TDSR ceiling once you have any other debt in the picture.
Does variable income get haircut the same way for an HDB loan?
Commission, bonus and rental income are typically included at a reduced percentage of their value in both the MSR and TDSR calculation, because they are considered less certain than fixed salary, which lowers the loan quantum a variable income household is offered.
Not sure what your real HDB loan ceiling is?
Winfred runs your actual MSR and TDSR numbers, with your real income mix and debt, before you commit to a flat you may not be able to finance.
Book a free 30 minute callWinfred Quek is an Associate Marketing Consultant at Crestbrick Pte Ltd (CEA Licence No. L31010886H). CEA R073319H. This page is for general information only and does not constitute financial, investment, or legal advice. Rates and rules reflect the position as at 5 Aug 2026; verify current figures with IRAS, HDB, or MAS before making any decision.