Compound interest
Explore how monthly contributions could grow over time.
How this works
Future value = P(1+i)^n + C[(1+i)^n − 1]/i; i = assumed annual nominal return ÷ 12. Zero-rate calculations sum contributions directly. Optional annual fee drag reduces the assumed nominal rate; yearly contribution growth and annual inflation adjust the projection. Beginning-of-month deposits receive one extra month of growth. Retirement target contribution solves the annuity formula with zero annual contribution growth.
Example
The illustration may use different inputs from the reproducible default inputs listed below.
With $1,000 initially and $100 at each month-end, one year at 0% produces $2,200. Inflation reduces purchasing power, not the displayed nominal balance.
- Starting amount
- 10000 USD
- Monthly contribution
- 200 USD
- Assumed annual return
- 5 %
- Time horizon
- 10 years
- Annual fee drag (%)
- 0
- Assumed annual inflation (%)
- 0
- Annual contribution increase (%)
- 0
- Monthly contribution timing
- End of month
- Projected future balance
- $47,526.55
Contributions use your chosen beginning/end-of-month timing. The retirement target calculation solves a constant monthly contribution with no annual escalation. Annual fee drag is subtracted from the nominal return; contributions increase once each year. Returns and inflation are user assumptions, not forecasts.
Scope and assumptions
Illustrative accumulation only, not financial advice. No tax rules, contribution limits, employer matches, benefits or guaranteed returns. Fees use a simplified annual rate subtraction. Does not estimate sustainable withdrawals.
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