Calculate how your investments grow over time with compound interest. Visualise the power of compounding with interactive charts and see the impact of regular monthly contributions.
Interactive charts showing your money growing over time
See the impact of regular monthly deposits on your savings
Choose monthly, quarterly, or annual compounding frequency
Compound interest is calculated using the formula A = P(1 + r/n)^(nt), where P is the principal, r is the annual rate, n is the compounding frequency per year, and t is time in years. For example, R100,000 invested at 10% compounded monthly for 10 years grows to R270,704 — that's R170,704 in interest alone. Adding R1,000 monthly contributions would grow the total to approximately R477,000.
The key to compound interest is time. The longer your money is invested, the more pronounced the "hockey stick" effect becomes. Starting early — even with small amounts — outperforms starting late with larger amounts.
Enter your investment details to see how your money grows
Enter your investment details and click calculate to see your projected growth with interactive charts
Understand why Albert Einstein reportedly called compound interest the "eighth wonder of the world"
Simple interest is calculated only on your original principal. If you invest R10,000 at 10% per year for 10 years, you earn R1,000 per year — R10,000 total, giving you R20,000.
Compound interest earns interest on both your principal and all previously accumulated interest. The same R10,000 at 10% compounded annually grows to R25,937 — R15,937 in pure interest, not just R10,000.
The longer the investment period, the greater the difference. Over 30 years, that same R10,000 at 10% simple interest becomes R40,000, while compound interest grows it to R174,494.
That's R5,937 more — 59% extra returns — from compounding alone.
A quick mental maths trick: divide 72 by your interest rate to estimate how many years it takes to double your money.
Common questions about compound interest, investment growth, and savings in South Africa
Knowing your projected growth is just the start. Accounter helps you track your actual investments and assets in one place.
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