Compound interest calculator
See how a lump sum and monthly contributions grow over time — with a year-by-year breakdown of contributions vs. interest earned.
Future value
$56,435.28
Total contributed
$25,000.00
Total interest earned
$31,435.28
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Growth over time
$56,43520 yr
| Year | Start balance | Contributions | Interest earned | End balance |
|---|---|---|---|---|
| 1 | $1,000.00 | $1,200.00 | $118.78 | $2,318.78 |
| 2 | $2,318.78 | $1,200.00 | $214.11 | $3,732.89 |
| 3 | $3,732.89 | $1,200.00 | $316.34 | $5,249.23 |
| 4 | $5,249.23 | $1,200.00 | $425.95 | $6,875.18 |
| 5 | $6,875.18 | $1,200.00 | $543.50 | $8,618.68 |
| 6 | $8,618.68 | $1,200.00 | $669.53 | $10,488.21 |
| 7 | $10,488.21 | $1,200.00 | $804.68 | $12,492.89 |
| 8 | $12,492.89 | $1,200.00 | $949.60 | $14,642.49 |
| 9 | $14,642.49 | $1,200.00 | $1,104.99 | $16,947.49 |
| 10 | $16,947.49 | $1,200.00 | $1,271.62 | $19,419.11 |
| 11 | $19,419.11 | $1,200.00 | $1,450.30 | $22,069.40 |
| 12 | $22,069.40 | $1,200.00 | $1,641.89 | $24,911.29 |
| 13 | $24,911.29 | $1,200.00 | $1,847.33 | $27,958.62 |
| 14 | $27,958.62 | $1,200.00 | $2,067.62 | $31,226.24 |
| 15 | $31,226.24 | $1,200.00 | $2,303.83 | $34,730.07 |
| 16 | $34,730.07 | $1,200.00 | $2,557.13 | $38,487.20 |
| 17 | $38,487.20 | $1,200.00 | $2,828.73 | $42,515.93 |
| 18 | $42,515.93 | $1,200.00 | $3,119.97 | $46,835.90 |
| 19 | $46,835.90 | $1,200.00 | $3,432.26 | $51,468.15 |
| 20 | $51,468.15 | $1,200.00 | $3,767.12 | $56,435.28 |
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How this is calculated
Each period, interest is calculated on the running balance — contributions included — and added to it, so interest itself starts earning interest. Monthly contributions are added at the start of each month, compounding at the frequency you choose.
This is an educational estimate, not financial advice.