See how your money grows — with charts, scenarios & inflation adjustment
Our advanced compound interest calculator features interactive Chart.js graphs showing your investment growth over time, inflation-adjusted values, scenario comparison to test different interest rates, a detailed year-by-year breakdown table, and CSV export. Understand the true power of compound interest with real purchasing power estimates. All calculations run in your browser — no data is sent anywhere.
Albert Einstein allegedly called compound interest 'the eighth wonder of the world.' Whether he said it or not, the math is remarkable: money earning interest on previously earned interest creates exponential growth over time. A $10,000 investment at 7% annual return grows to $19,672 in 10 years, $38,697 in 20 years, and $76,123 in 30 years — most of that growth comes from compounding, not your original investment. The compounding frequency matters too: daily compounding yields slightly more than annual for the same rate. Understanding compound interest is fundamental to retirement planning, debt management (credit cards compound against you), and evaluating investment options. This calculator includes monthly contribution options to show how regular investing amplifies the compounding effect.
$10,000 at 5% for 10 years: annually = $16,289, monthly = $16,470, daily = $16,487. More frequent compounding earns slightly more, but the difference narrows at higher frequencies. Daily vs monthly is minimal.
Divide 72 by your annual return rate to estimate how many years to double your money. At 7%: 72/7 ≈ 10.3 years. At 10%: 72/10 = 7.2 years. It's a quick mental math shortcut with surprising accuracy.
Inflation erodes purchasing power. If your investment earns 7% and inflation is 3%, your real return is roughly 4%. For accurate long-term planning, use 'real return' (nominal rate minus inflation) in your calculations.
Compare interest rates. Credit card debt at 20% compounds against you faster than investments at 7% grow for you. Pay high-interest debt first (mathematically), though some prefer the psychological wins of small debt payoffs (snowball method).
Simple interest is calculated only on the principal. Compound interest is calculated on principal plus accumulated interest. Over long periods, the difference is massive: $10,000 at 7% for 30 years is $31,000 simple vs $76,123 compound.