Compound Interest Calculator
See how money grows with compound interest and contributions over time, with a year-by-year breakdown. Add contributions to see how consistent saving interacts with compounding.
Inputs
$
$
%
Results
Ending balance
$145,180.47
Total contributions$58,000.00
Total interest$87,180.47
Approx. monthly rate0.5833%
Year-by-year growth
| Year | Contributions | Interest | Balance |
|---|---|---|---|
| 1 | $12,400.00 | $815.88 | $13,215.88 |
| 2 | $14,800.00 | $1,864.23 | $16,664.23 |
| 3 | $17,200.00 | $3,161.86 | $20,361.86 |
| 4 | $19,600.00 | $4,726.80 | $24,326.80 |
| 5 | $22,000.00 | $6,578.36 | $28,578.36 |
| 6 | $24,400.00 | $8,737.26 | $33,137.26 |
| 7 | $26,800.00 | $11,225.74 | $38,025.74 |
| 8 | $29,200.00 | $14,067.59 | $43,267.59 |
| 9 | $31,600.00 | $17,288.39 | $48,888.39 |
| 10 | $34,000.00 | $20,915.51 | $54,915.51 |
| 11 | $36,400.00 | $24,978.33 | $61,378.33 |
| 12 | $38,800.00 | $29,508.35 | $68,308.35 |
| 13 | $41,200.00 | $34,539.34 | $75,739.34 |
| 14 | $43,600.00 | $40,107.52 | $83,707.52 |
| 15 | $46,000.00 | $46,251.72 | $92,251.72 |
| 16 | $48,400.00 | $53,013.58 | $101,413.58 |
| 17 | $50,800.00 | $60,437.75 | $111,237.75 |
| 18 | $53,200.00 | $68,572.11 | $121,772.11 |
| 19 | $55,600.00 | $77,468.00 | $133,068.00 |
| 20 | $58,000.00 | $87,180.47 | $145,180.47 |
How to use it
- Enter starting principal and interest rate.
- Choose a time horizon and compounding frequency.
- Add recurring contributions if you want to model saving over time.
- Review ending balance, total contributions, and interest earned.
Key formulas
- Compound growth
- FV = P × (1 + r/n)^(n×t)
FAQ
Compound interest means you earn interest on both your original principal and on previously earned interest. Over long periods, compounding can significantly increase growth.
It’s how often interest is applied (daily, monthly, quarterly, etc.). More frequent compounding slightly increases growth when rates are positive.
Regular contributions can be a major driver of the ending balance. Contributing earlier and more consistently usually increases growth because more money compounds for longer.
No. Real returns can be reduced by taxes, fees, and inflation.
No. This uses a constant rate. Real investments fluctuate year to year.
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Disclaimer
Educational estimates only. Not financial advice. Returns are not guaranteed.