Tools
Compound growth calculator
The balance grows, then the contribution is added. Annual mode adds it once a year. Monthly mode splits the same annual amount into twelve end-of-month deposits. A 5% default is a real planning rate, not a forecast.
Arc · Published September 18, 2026 · Updated September 18, 2026
Assumptions
- Default 5% is a real return, after inflation.
- It is not a forecast.
- Monthly mode converts that annual rate into an equivalent monthly rate. It does not divide the rate by 12.
Balance
$529,456
After 20 years, in today's dollars if the rate is real.
FV = PV × (1+r)^n + PMT × (((1+r)^n − 1) ÷ r)
Annual mode uses the formula below with an end-of-year PMT. Monthly mode uses m = (1+r)^(1/12) − 1 and a deposit of PMT ÷ 12. If r is 0, both modes equal PV + annual contribution × n.
FV = PV × (1+r)^n + PMT × (((1+r)^n − 1) ÷ r)
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Educational estimate only. Not tax, legal, or investment advice, and not a prediction of what your accounts will do. Methodology