// TOOLS · COMPOUND INTEREST CALCULATOR
Compounding Interest 🪄 Compound interest is how money grows on itself. Plug in a principal, an annual interest rate, and a duration, and see what it becomes. Watch each year add up.
// OUTPUT
$19,672 USD TOTAL
+$9,672 EARNED IN INTEREST
$10,000 grows to $19,672 in 10 years at 7% . You earn $9,672 in compound interest.
// YEAR BY YEAR
×0 $10,000 ×1 $10,700 +$700 ×2 $11,449 +$749 ×3 $12,250 +$801 ×4 $13,108 +$858 ×5 $14,026 +$918 ×6 $15,007 +$982 ×7 $16,058 +$1,051 ×8 $17,182 +$1,124 ×9 $18,385 +$1,203 ×10 $19,672 +$1,287 // HOW IT WORKS
How the formula works
FORMULA total = principal × (1 + rate)^years
WHY ANNUAL Annual compounding keeps the math readable. Monthly compounding is barely different over decades and would only add precision noise to the year-by-year sequence below. RULE OF 72 Money roughly doubles in 72 ÷ rate years. Five doublings is 32×. Ten is 1024×. TheDouble Calculator lives next door if you want to think in doublings instead.