Bond Repayment Calculator (South Africa)
Home price, deposit, prime-linked rate — your monthly bond, live.
How this is calculated
bond = price × (1 − deposit%) · M = bond × r(1+r)ⁿ ÷ ((1+r)ⁿ − 1), r = rate ÷ 12
Worked example: a R1,850,000 home with 10% down at 11.25% over 20 years → bond of R1,665,000 and a monthly repayment of R17,470, with roughly R2.53m of interest over the term. Push the term slider to 30 years and the repayment drops — but the total interest climbs past R4m, which is the trade-off the two result lines keep honest.
The South African specifics
SA bonds are typically prime-linked (floating), so your repayment moves when the Reserve Bank moves rates — budget headroom for a percent of drift. Banks' affordability checks want the repayment near 30% of gross income, shown live in the result. And remember the cash-on-top costs: transfer duty (on homes above the duty-free threshold), bond registration, and attorneys — commonly six figures on a mid-market home, payable before the bond starts.
Frequently asked questions
How is a bond repayment calculated in South Africa?
Same amortization math banks worldwide use, at South African numbers: the amount after your deposit, at your negotiated rate (quoted relative to prime, currently prime ±), over 20 or 30 years. This page defaults to a 10% deposit, prime-linked 11.25%, and 20 years — edit everything.
What deposit do I need for a bond?
100% bonds exist (especially for first-time buyers), but a 10% deposit meaningfully lowers both the rate banks offer and your monthly repayment, and 20% often unlocks the best pricing. The deposit slider shows the effect on the repayment instantly.
What income do I need for a given bond?
South African banks generally want the repayment under about 30% of gross monthly income. The result panel shows that income line for the current numbers — for a R17,470 repayment you would need roughly R58,200 gross per month.
Prime, prime minus, prime plus — what am I actually paying?
Most SA bonds float against the prime rate. "Prime minus 1" at 11.75% prime means you pay 10.75%. Your rate depends on your credit profile and deposit — enter the rate you were quoted, and remember a floating rate moves when prime does.
Do transfer costs go into the bond?
Transfer duty and attorney costs are usually paid cash on top of the deposit (some banks finance costs into a 105% bond at worse rates). Budget them separately — on a R1.85m home they can run well past R100,000. This calculator models the bond itself.