Compound Interest Calculators

Compound interest calculator for savings and investment growth, with clear charts, side-by-side plan comparisons, goal solving and detailed PDF reports. The calculator, chart and Details are free; comparing plans, goals, saved plans and PDF and CSV reports are in the one-time Full Calculator purchase (no subscription). SEE WHAT YOUR MONEY COULD BECOME Enter a starting balance, annual return, timeline and regular contribution. See Future Balance and Net Gain update as you explore. A readable chart shows the path, with month or year labels that adapt to your timeline. SEE WHAT A CHANGE COULD DO Keep your current plan beside an editable alternative. Compare contributions, returns, duration and timing without overwriting your original plan. Apply the alternative only when you choose. FIND A PATH TO YOUR GOAL Solve for the regular contribution, time to reach a target, or required annual return. Each solver asks a clear question and shows the relevant assumptions. A required return is a mathematical result, not a prediction or guarantee. UNDERSTAND THE NUMBERS Contribution and compounding frequencies are independent. Choose beginning- or end-of-period contributions, include extra months, compare return assumptions and see an inflation-adjusted balance in today's purchasing power. KEEP AND SHARE THE WHOLE PLAN Share a PDF with your chart, results, assumptions, return comparisons, annual schedule and complete monthly appendix. Export a CSV with results, inputs and monthly contributions, growth and balances. Plan links let installed recipients reopen the same inputs. MADE FOR EVERYDAY USE Your last valid inputs are remembered. Save plans locally with the Full Calculator. Use System, Light or Dark appearance. Calculations work offline, with no account, ads, subscription or tracking. The Full Calculator is a single optional purchase. Hypothetical educational calculations only. Returns are not guaranteed. Taxes, fees, market volatility and irregular dated payments are excluded. Annual Return is nominal; Details also shows effective annual return. Currency formatting does not perform currency conversion. Saved plans do not automatically sync between devices.