📈 Compound Interest Calculator
Calculate how investments grow with compound interest and regular contributions over any time period.…
The Power of Compound Interest
Compound interest is interest earned on both your original principal and the interest already accumulated. Often called "the eighth wonder of the world," it causes wealth to grow exponentially — the longer money compounds, the more dramatic the effect.
A = Future Value, P = Principal, r = Annual Rate, n = Compounds/Year, t = Years
The Rule of 72
A quick mental shortcut: divide 72 by your annual interest rate to estimate how many years it takes your money to double. At 8%, your money doubles every 9 years (72 ÷ 8 = 9). At 12%, every 6 years.
Compounding Frequency Matters
The more often interest compounds, the more you earn. Daily compounding yields slightly more than monthly, which yields more than annual. However, the difference between daily and monthly is often less than 0.1% — the interest rate itself has far more impact than compounding frequency.