i What this calculator does
Answers the question every South African buyer asks before looking at listings: how much bond will a bank give me? It applies the two tests banks use. The first is the rule of thumb that the instalment should not exceed 30% of gross income. The second, which the National Credit Act requires, is an affordability assessment: what is actually left after tax, living expenses and existing debt. The lower of the two sets your maximum instalment, and the calculator converts that into a loan amount at your rate and term, then adds your deposit to give a purchase price.
Most buyers are surprised that existing debt matters more than income. R3,500 of car and card repayments removes roughly R350,000 of bond capacity at 2026 rates, which is why clearing short-term debt before applying is the standard advice.
An estimate using the common 30% guideline and a basic affordability test. Each bank applies its own credit scoring and the National Credit Act assessment; the amount you are offered may differ. Not financial advice.
See also: Dividend Withholding Tax Calculator.
Frequently asked questions
What is the 30% rule for home loans?
A guideline most South African banks apply: the bond instalment should not exceed about 30% of your gross monthly income. It is a ceiling, not an entitlement; the affordability assessment can set a lower limit.
Why does the calculator ask for net income and expenses as well?
Because the National Credit Act requires lenders to assess what you can actually afford after tax, living costs and existing debt. A buyer with high expenses may qualify for less than 30% of gross; one with low expenses rarely gets more.
Does a joint application help?
Yes. Combined gross income raises the 30% ceiling and combined net income raises the surplus. Both applicants' debts and expenses count too.
How much deposit do I need?
Banks grant 100% bonds to good profiles, but a deposit of 10% or more usually earns a lower rate and reduces the instalment. You also need cash for transfer duty, bond registration and conveyancing, which the deposit does not cover.
What interest rate should I use?
Prime, 10.5% in 2026/27, unless you have an offer. Use a rate half a percent higher than prime to stress-test the result; a rate increase after you buy does not change the bank's view of what you qualified for.
Does the calculator include rates, levies and insurance?
No. Municipal rates, sectional title levies, homeowner's insurance and maintenance come on top of the instalment and should sit in your expenses figure when you work out what you can carry.
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