Bond repayment calculator

This bond repayment calculator runs the full amortisation schedule on a South African home loan, twice, so you can compare two plans side by side: repayment, total interest and the month the bond is paid off.

The mechanics are standard SA bond mechanics. Repayments are worked out on the rate and term you set, held level across the loan. Almost every home loan in the country tracks prime rather than a fixed contract rate, so the rate you enter is whatever your bank quoted you against prime, and prime moves when the Reserve Bank's Monetary Policy Committee moves the repo rate. Testing a rise is a separate job, and the rate shock tool does it.

Have these ready:

  • the purchase price and your deposit, or the outstanding balance if the bond already exists
  • the rate your bank quoted, and the term in years
  • any extra monthly payment, plus any lump sum and the month it lands
  • your take-home pay and other monthly debt, for the debt-load gauge at the bottom

Results come in three layers. The stat cards compare the two scenarios on monthly payment, payoff time and total interest, and give the interest saved going from one to the other. The true-price strip shows everything that leaves your account over the term, deposit and principal and every rand of interest, set against the purchase price. Then the charts: balance falling, the principal-versus-interest split of each payment, cumulative interest, and a schedule you can open year by year down to the month.

Early payments on an SA bond are mostly interest. That is why money aimed at the principal moves the payoff date so hard, and the schedule shows how hard at your own numbers.

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Questions

What is the monthly repayment on a R1,000,000 bond in South Africa?

At the prime rate of 10.75%, in force from 25 September 2026, a R1,000,000 bond over 20 years costs R10,152 a month. Over the full term you pay R2,436,549, and R1,436,549 of that is interest. Banks price many home loans above or below prime, so enter the rate your bank quoted.

How much does an extra R2,000 a month save on a bond?

On the same R1,000,000 bond at 10.75%, an extra R2,000 a month pays it off in 12 years and 6 months instead of 20 years. Total interest falls from R1,436,549 to R820,794, a saving of R615,755.

How is prime linked to the repo rate?

Prime is the SARB repo rate plus 3.5 percentage points. With the repo rate at 7.25%, prime is 10.75%. Most South African home loans track prime, so when the Monetary Policy Committee moves the repo rate, the bond repayment moves a few weeks later.

Money Cat is an information tool, not financial advice. Confirm any figure that matters with your bank, lender or a registered professional.