Compound Interest Calculator
Use this compound interest calculator to estimate how your savings or investments could grow over time. Enter an initial balance, an annual interest rate, the compounding frequency, and optional recurring contributions to see your projected future value, total contributions, and interest earned.
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Results
- Future value
- $167,072.11
- Total contributions
- $58,000.00
- Total interest earned
- $109,072.11
Chart vs table: Use the chart for a quick visual of growth over time, or switch to the table for the year-by-year balance and contributions.
Projected growth over time
Year-by-year balance vs. total contributions.
Assumptions
- Returns are assumed constant — real-world rates fluctuate year to year.
- Contributions are assumed to be made on a fixed schedule and amount.
- Taxes, fees, and inflation are not included in the projected balance.
- End-of-period vs. beginning-of-period contributions affect the result slightly.
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Compound Interest Print Summary
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- Starting amount
- $10,000.00
- Annual rate
- 8.00%
- Years
- 20
- Compounds per year
- 12
- Recurring contribution
- $200.00
- Future value
- $167,072.11
- Total contributions
- $58,000.00
- Total interest earned
- $109,072.11
Educational estimate only. Actual investment performance may differ.
Formula
FV = P × (1 + r/n)^(n·t)
FVcontrib = PMT × [((1 + r/n)^(n·t) − 1) / (r/n)]
If contributions occur at the beginning of each period, multiply the contribution future value by (1 + r/n).
How to calculate
- Start with your initial investment.
- Convert the annual interest rate into a decimal.
- Choose how often interest compounds.
- Multiply the number of years by the compounding periods.
- Apply the compound interest formula.
- If you make regular contributions, add the future value of those payments.
- The final result is your projected ending balance.
Worked example
Invest $10,000 at 8% annually, compounded monthly, for 20 years: FV = 10,000 × (1 + 0.08/12)^(12×20) ≈ $49,268.03.
Frequently asked questions
What is compound interest?
Compound interest is interest earned on both your original money and previously earned interest.
Why does compounding matter?
The more often money compounds and the longer it stays invested, the more growth potential it has.
Is monthly compounding better than annual compounding?
Monthly compounding generally produces a slightly higher future value than annual compounding when the rate and time period are the same.
Can I use this calculator for savings and investing?
Yes. It can be used for savings accounts, retirement investing, general investing, and other long-term growth estimates.
Related calculators
This calculator provides estimates only and does not guarantee future investment performance.