One signed cash-flow equation
PV × (1+i)^n + PMT × annuity factor + FV = 0. In this convention, money paid out is negative and money received is positive. An initial deposit of −1,000 and a later receipt of +1,628.89 can describe the same ten-year 5% example. Signs describe direction, not whether an outcome is good or bad.
Keep the period unit consistent
Rate is entered per period and n counts those same periods. For monthly payments under a matching 12% nominal monthly-compounded annual rate, enter a periodic rate of 1 and twelve periods for a year. A quoted effective annual return requires an exponential conversion instead of simple division.
Why a solver may refuse a scenario
Some inputs have no solution or do not identify a unique rate. With zero time, a rate cannot be recovered from an unchanged lump sum. Rate solving is bounded to −5% through 100% per period and rejects opposing present-value/payment signs that may create multiple roots. The period solver searches zero through 2,400 periods and reports failure rather than inventing a result.
Questions about this calculation
How can I check the inputs behind the result?
Open “Show calculation & assumptions” for the formula and timing conventions, then inspect the breakdown. Export CSV to keep the last calculated inputs and numerical results together.
Does this include taxes or changing market returns?
No tax calculation or variable market-return path is included. The task-specific assumptions above describe the scope. Calculated values are conditional on the inputs, not personalized recommendations.
Learn more
Start with the step-by-step future value formula guide.
Open the formula guide →How to calculate future value · Spreadsheet calculations · All learning guides
Use these figures to explore assumptions. Actual interest, returns, fees, taxes and purchasing power can differ.