Formula
Principal grows by A = P(1 + r/n)^(nt). Monthly contributions are compounded after each contribution period. The inflation-adjusted value discounts the final balance by the inflation assumption over the full term.
Example
Starting with $1,000, adding $100 per month for 10 years at a 6% annual return compounded monthly produces a much larger balance than contributions alone. The result separates your contributions from estimated growth so you can see both pieces.
Common mistakes
Do not treat a steady return assumption as a promise. Investment returns vary, and fees, taxes and inflation can materially reduce real purchasing power.
What the result shows
The calculator separates nominal future value, total contributions, earned interest and an inflation-adjusted estimate. Use those figures together: a large future balance can look less impressive once contributions, time and purchasing power are visible.
Limitations
Returns are not guaranteed. Taxes, fees, variable returns and market volatility are not included. Inflation is a user-entered scenario assumption, not live CPI data.
References
- Investor.gov: financial tools and calculators, accessed 2026-05-14.
Last reviewed: 2026-05-14