📈 Compound Interest Calculator
Calculate compound interest with optional regular contributions. See how your investments grow over time with daily, monthly, quarterly, or yearly compounding.
Compound Interest Formula
A = P(1 + r/n)nt + PMT × [((1 + r/n)nt - 1) / (r/n)]
Where: A = final amount, P = principal, r = annual rate, n = compounding frequency, t = years, PMT = periodic contribution.
The Power of Compounding
| Years | $10K @ 5% | $10K @ 7% | $10K @ 10% |
|---|---|---|---|
| 10 | $16,289 | $19,672 | $25,937 |
| 20 | $26,533 | $38,697 | $67,275 |
| 30 | $43,219 | $76,123 | $174,494 |
Frequently Asked Questions
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. It causes your money to grow exponentially over time.
More frequent compounding means more returns. Daily compounding yields slightly more than monthly, which yields more than yearly.
The Rule of 72 estimates how long it takes to double your money: divide 72 by the annual interest rate. At 6%, it takes approximately 12 years to double.
Simple interest is calculated only on the principal. Compound interest is calculated on principal plus accumulated interest, producing significantly higher returns over time.