Mortgage & Bond Repayment Calculator
Estimate your monthly mortgage repayment in South African rand. A mortgage is also called a home loan or bond: compare loan amounts, annual interest rates and repayment terms before applying.
Calculate your monthly mortgage repayment
Adjust the figures below for an indicative estimate. Your result updates as you type.
Estimated monthly repayment
R 16 256
Indicative principal-and-interest repayment. Bank fees, insurance and rate changes are excluded.
The 30% rule
30% of your income: R 15 000 per month.
This repayment uses 32.5% of your gross monthly income.
Above the 30% guideline
You would need a gross monthly income of about R 54 185 for this repayment to fall within 30%.
How mortgage repayments are calculated
The monthly estimate uses your loan amount, annual interest rate and number of monthly payments to calculate a principal-and-interest instalment.
A larger loan or higher interest rate increases your repayment. A longer term can lower the monthly instalment but increases total interest if the rate stays the same. The rate shown is an editable example, not a current bank quote. Fees, insurance and future rate changes are excluded, so this estimate is not a guarantee of affordability or approval.
How the 30% rule works
South African banks use the 30% rule as a first affordability test on every home loan application.
The rule says your monthly bond repayment should not exceed 30% of your gross (before tax) monthly household income. On a combined income of R50 000, that caps the repayment at roughly R15 000 a month.
Banks apply it as a starting point and then subtract your other credit commitments, living expenses and a rate-increase buffer. Staying under 30% keeps room in your budget for rates and taxes, levies, insurance, maintenance and future interest rate hikes.
Worked example
- Gross monthly income: R50 000
- 30% guideline: R15 000 maximum repayment
- Repayment on R1 500 000 over 20 years at 11.75%: about R16 300
- Result: slightly above the guideline — a larger deposit, longer term or lower purchase price brings it back in range
The 30% rule is a guideline, not a credit decision. A Gateway pre-approval confirms what you actually qualify for across participating banks.
Make your next property decision with confidence
- Compare the effect of a larger deposit
- See how a shorter term reduces total interest
- Apply online and compare participating banks
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One online application, compared across leading South African banks, with an experienced mortgage specialist guiding you from pre-approval to registration.
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