Compound Interest Calculator

See how a starting amount and monthly contributions grow over time. Optionally adjust for inflation.

R
R
%
%
Final balanceR727 978.39
Total contributionsR250 000.00
Interest earnedR477 978.39
In today's moneyR274 367.40
ContributionsInterest
Year-by-year breakdown
YearContributionsInterestBalance
1R 22 000R 1 446R 23 446
2R 34 000R 4 153R 38 153
3R 46 000R 8 239R 54 239
4R 58 000R 13 835R 71 835
5R 70 000R 21 081R 91 081
6R 82 000R 30 133R 112 133
7R 94 000R 41 159R 135 159
8R 106 000R 54 345R 160 345
9R 118 000R 69 894R 187 894
10R 130 000R 88 028R 218 028
11R 142 000R 108 988R 250 988
12R 154 000R 133 040R 287 040
13R 166 000R 160 474R 326 474
14R 178 000R 191 607R 369 607
15R 190 000R 226 786R 416 786
16R 202 000R 266 391R 468 391
17R 214 000R 310 837R 524 837
18R 226 000R 360 578R 586 578
19R 238 000R 416 111R 654 111
20R 250 000R 477 978R 727 978

Last updated: 17 April 2026

This calculator is a tool for estimation. For tax filing or financial advice, consult a registered tax practitioner, financial advisor, or SARS.

How compound interest works

Compound interest is interest earned on interest. Each period, returns are added to the principal so the next period's growth is calculated on a larger base. Over decades, this turns small monthly contributions into substantial wealth.

Tips for South Africans

  • Use a TFSA before a taxable account where possible.
  • Maximise RA contributions — you get a tax deduction up to the cap.
  • Time in the market beats timing the market. Start early, contribute regularly.

Frequently asked questions

Related: Retirement Annuity · PAYE

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