Compound Interest Calculator
Calculate compound growth with recurring deposits, deposit timing, investment fees and inflation. Free, with no signup.
Reviewed October 25, 2026
Short answer
Deposits and time both matter. Starting with $10,000 and adding $100 at each month end for 10 years at 6% APR compounded monthly produces about $34,582 before taxes, or $25,732 in today's purchasing power at 3% inflation.
Free to use. No signup. Results update as you edit.
Total nominal deposits: $22,000. Fees and the growth lost on those fees reduce the ending balance by $0.
Scale: $0 to $25,732. Exact values in the table below.
Yearly compound-growth balances
Scroll horizontally on small screens.
| Year | Future dollars | Today's dollars |
|---|---|---|
| 1 | $11,850 | $11,505 |
| 2 | $13,815 | $13,022 |
| 3 | $15,900 | $14,551 |
| 4 | $18,115 | $16,095 |
| 5 | $20,466 | $17,654 |
| 6 | $22,961 | $19,230 |
| 7 | $25,611 | $20,824 |
| 8 | $28,424 | $22,438 |
| 9 | $31,411 | $24,074 |
| 10 | $34,582 | $25,732 |
Fixed nominal deposits and a constant nominal APR. Fees are an annual percentage of assets, not a flat dollar charge. Real-dollar results discount the ending balance by inflation.
This is an educational estimate, not tax or financial advice. Figures reflect the law year shown and the inputs you provide. Consult a qualified professional before acting.
Sources
- Compound Interest Calculator — U.S. Securities and Exchange Commission
The future-value compounding relationship used to carry today's portfolio to retirement age.
Accessed September 3, 2026
How it’s calculated
- Convert nominal APR into annual growth using (1 + APR ÷ compounding frequency)^frequency. This is not the same input as an effective annual yield.
- Multiply annual growth by (1 − annual fee). Convert this net annual factor to an equivalent growth factor for each deposit interval, including fractional compounding periods.
- Add each fixed nominal deposit either before or after the deposit-period growth, depending on your timing choice. Repeat for the selected years.
- Divide future-dollar balances by (1 + inflation)^years for today's purchasing power. Compare with a no-fee path to show fees plus lost growth.
Worked monthly compounding example
- Initial / monthly deposit
- $10,000 / $100
- APR / compounding
- 6% / monthly
- Timing / horizon
- Month end / 10 years
- Fee / inflation
- 0% / 3%
Result
$34,582 future dollars; $25,732 today's dollars; $22,000 total nominal deposits.
The independent future-value formula is $10,000 × 1.005^120 + $100 × (1.005^120 − 1) ÷ 0.005 = $34,581.90. Divide by 1.03^10 to obtain $25,732.18 in today's dollars.
What this calculator does not cover
- No taxes, contribution limits, variable returns, flat transaction fees or withdrawals.
- Deposits do not increase with inflation. Fee drag includes both fees and foregone growth, not just cash fees paid.
- Compounding between deposit dates uses equivalent fractional-period growth. Actual bank crediting calendars, daily day-count conventions and fund fee deductions may differ.
- Investment returns are not guaranteed; an assumed APR is not a forecast.
Frequently asked
- Why does beginning-of-period timing change the result?
- Each deposit earns one extra deposit interval of growth. With a positive net return that raises the final balance; with a negative net return it can lower it.
- What does inflation-adjusted mean?
- It expresses the future balance in today's purchasing power. It does not change the nominal balance shown by a financial institution.
Related reading
Explore more worked examples on the retirement planning blog.