How this calculation works
This calculator uses: A = P × (1 + r/n)ⁿᵗ. Enter your values above to get an immediate result. Results are rounded for readability.
Using the compound interest calculator
Start by entering values in the units shown. The result updates immediately, and the shareable link preserves your inputs without creating a separate indexable page. Use this as a clear estimate and check important assumptions before relying on it.
Common questions
What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, it grows exponentially — often called 'interest on interest'.
How often should interest compound for maximum growth?
The more frequently interest compounds, the more you earn. Daily compounding gives slightly more than monthly, which gives more than annual. For most investments and savings accounts, monthly compounding is standard.
What is the Rule of 72?
The Rule of 72 is a quick way to estimate how long it takes to double your money. Divide 72 by your annual return rate. For example, at 8% return, your money doubles in approximately 72 ÷ 8 = 9 years.
What is the difference between compound interest and simple interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on the principal plus all previously earned interest. Over long periods, compound interest grows significantly more.