Interest rate change calculator

Find out what a rise or cut in interest rates does to your monthly instalment.

Your bond, car loan or personal loan balance.

Look on your statement. Your lender’s rate may differ from the example.

Your instalment goes up by

R 169.59

Instalment now
R 10 152.29
Instalment after the change
R 10 321.88
Over a year
+ R 2 035
Interest over the rest of the loan
+ R 40 703

This assumes the loan keeps the same term and the new rate applies to the rest of it. Some lenders keep your instalment the same and change the term instead. Ask yours.

Estimates only. Not financial advice.

What each change would do

Instalment at different interest rates
ChangeRateInstalmentDifference a monthInterest over the loan
−1.009.75%R 9 485.17− R 667R 1 276 440
−0.5010.25%R 9 816.43− R 336R 1 355 944
−0.2510.50%R 9 983.80− R 168R 1 396 112
No change10.75%R 10 152.29R 0R 1 436 549
+0.2511.00%R 10 321.88+ R 170R 1 477 252
+0.5011.25%R 10 492.56+ R 340R 1 518 214
+1.0011.75%R 10 837.07+ R 685R 1 600 897

Recent policy rate decisions

SARB policy rate: decisions that changed the rate
DecisionNew policy rateChange
25 September 20267.25%+0.25
29 May 20267.00%+0.25
21 November 20256.75%−0.25
1 August 20257.00%−0.25
30 May 20257.25%−0.25
31 January 20257.50%−0.25

How the interest rate change calculator works

Last updated 10 November 2026

When the Reserve Bank changes its policy rate, lenders usually change the rate on loans linked to prime. This calculator shows what that does to your instalment and to the interest you pay over the rest of the loan.

How it works

  • Enter what you still owe, your current rate and the years left.
  • Choose a rise or a cut. The tool works out the level instalment now and after the change.
  • The loan keeps the same term, so only the instalment and the total interest move.

Worked example

With the starting figures:

  1. A loan of R 1 000 000 at 10.75% over 20 years costs R 10 152.29 a month now.
  2. After the change it costs R 10 321.88, a difference of R 169.59 a month.
  3. Over the rest of the loan the interest changes by R 40 703.

Why a small change adds up

A quarter of a percentage point sounds small. On a large loan over many years it becomes a real amount each month and a bigger one in total. The table below the result shows the effect of larger moves too, so you can see how much room your budget has if rates rise.

The policy rate and your rate

The policy rate is set by the Reserve Bank. The latest decision on our list was on 25 September 2026, when it moved to 7.25%. Your own rate depends on your lender and on your agreement, so use the rate on your statement and not the policy rate in the box.

Cuts and rises both shown

The same sums work in both directions. A cut lowers the instalment and the total interest. If you keep paying the old instalment after a cut, the extra goes off the balance, which this tool does not model. Try the bond repayment calculator for extra payments.

What it does not cover

Fees, insurance, balloon payments, linked savings accounts and variable-rate offers are not included. Nor does it predict what the Reserve Bank will do. It shows the arithmetic of a change you choose.

Things to watch

  • Use your own rate from your lender. The starting figure is an example.
  • The Reserve Bank’s decisions are not forecast here.

Related: the bond repayment calculator, the car finance calculator and the rates and prices dashboard. Read the full disclaimer.

Questions people ask

What is the repo rate?

The Reserve Bank’s policy rate, which people still call the repo rate. It is 7.25% since the decision on 25 September 2026. The Reserve Bank changes it at its Monetary Policy Committee meetings.

How does a repo rate change reach my bond?

Banks set their own prime lending rate, and it normally moves by the same amount as the policy rate. Bonds, car loans and many personal loans are priced off prime, so a change in the policy rate usually changes your instalment soon after.

Will my instalment always change?

Not always. A fixed-rate loan does not move. Some lenders keep your instalment the same and change how long the loan runs. Check your agreement or ask your lender.

When is the next announcement?

The next Monetary Policy Committee meeting on our list ends on 19 November 2026. Always check the Reserve Bank’s calendar for confirmed dates.

Is anything stored?

No. Your numbers stay in the page.

Bond repayment calculatorMonthly repayments, total interest and the effect of paying extra.Car finance calculatorMonthly instalments with deposit, trade-in and balloon payment.Rates and prices dashboardThe policy rate and its history, the next rate decision and the latest fuel price change.

Figures last checked on 10 November 2026 for the 2026/27 tax year. Sources: SARB monetary policy statements, SARB Monetary Policy Committee calendar.

Estimates only, based on 2026/27 figures. Not financial advice. Read the full disclaimer.