Enter principal, annual rate, and investment years to calculate compound interest returns. Supports monthly contribution mode with visual growth charts.
Lump Sum: FV = PV x (1 + r/n)^(n x t)
Monthly Contributions: FV = PV x (1 + r/n)^(n x t) + PMT x [((1 + r/n)^(n x t) - 1) / (r/n)]
Where PV = initial principal, PMT = monthly contribution, r = annual rate, n = compounding frequency per year, t = years
Rule of 72: Doubling time (years) = 72 / Annual Rate (%)
Free online compound interest calculator. Supports lump sum and monthly contribution modes. Enter principal, annual rate, and years to calculate returns with yearly tables and growth charts. Great for budgeting, homework, and everyday calculations. It is completely free, requires no registration, and all processing happens locally in your browser — your data never leaves your device.
Yes, it is 100% free with no registration and no usage limits.
Absolutely. All processing runs locally in your browser — nothing is uploaded to any server.
Free online compound interest calculator. Supports lump sum and monthly contribution modes. Enter principal, annual rate, and years to calculate returns with yearly tables and growth charts. Suitable for developers, students, and everyday users.