Compound Interest Calculator
Project how an initial balance changes when interest is repeatedly added to the balance.
Visual summary
Projected compound growth
The solid line shows the projected balance; the dashed line shows the starting principal.
| Period | Projected balance | Starting principal |
|---|---|---|
| Start | $200,000 | $200,000 |
| Year 1.3 | $215,537 | $200,000 |
| Year 2.5 | $232,280 | $200,000 |
| Year 3.8 | $250,324 | $200,000 |
| Year 5 | $269,770 | $200,000 |
| Year 6.3 | $290,727 | $200,000 |
| Year 7.5 | $313,311 | $200,000 |
| Year 8.8 | $337,650 | $200,000 |
| Year 10 | $363,879 | $200,000 |
| Year 11.3 | $392,146 | $200,000 |
| Year 12.5 | $422,610 | $200,000 |
| Year 13.8 | $455,439 | $200,000 |
| Year 15 | $490,819 | $200,000 |
| Year 16.3 | $528,947 | $200,000 |
| Year 17.5 | $570,037 | $200,000 |
| Year 18.8 | $614,319 | $200,000 |
| Year 20 | $662,041 | $200,000 |
| Year 21.3 | $713,470 | $200,000 |
| Year 22.5 | $768,894 | $200,000 |
| Year 23.8 | $828,624 | $200,000 |
| Year 25 | $892,994 | $200,000 |
| Year 26.3 | $962,364 | $200,000 |
| Year 27.5 | $1M | $200,000 |
| Year 28.8 | $1M | $200,000 |
| Year 30 | $1M | $200,000 |
Calculations happen locally in your browser.
How to use this calculator
- Enter principal, annual rate, years, and a whole number of compounding periods per year.
- Review the live result and use Copy result when you need to share it.
How the calculation works
Each period multiplies the balance by one plus the periodic interest rate. The number of periods equals years multiplied by compounds per year.
Formula
Final balance = principal × (1 + rate ÷ compounds)^(compounds × years)
Step-by-step calculation
- Enter principal, annual rate, years, and a whole number of compounding periods per year.
- Each period multiplies the balance by one plus the periodic interest rate. The number of periods equals years multiplied by compounds per year.
- Check the displayed result, then copy it if needed.
Worked example
$1,000 compounded annually at 5% for 10 years grows to about $1,628.89.
Risk guidance
Frequently asked questions
Are additional contributions included?
No. This version compounds one starting principal without periodic deposits or withdrawals.
Does this tool send my inputs anywhere?
No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.
How should I use the result?
Check that the entered units and values match your situation, especially around dates, breaks, and rounding.
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