Compound Interest Calculator
See how your money grows with compounding and contributions.
Future value
$105,376.96
Total contributed
$49,000.00
Total interest
$56,376.96
| Year | Balance | Contributed | Interest |
|---|---|---|---|
| 1 | $3,546.06 | $3,400.00 | $146.06 |
| 2 | $6,270.34 | $5,800.00 | $470.34 |
| 3 | $9,185.33 | $8,200.00 | $985.33 |
| 4 | $12,304.36 | $10,600.00 | $1,704.36 |
| 5 | $15,641.72 | $13,000.00 | $2,641.72 |
| 6 | $19,212.70 | $15,400.00 | $3,812.70 |
| 7 | $23,033.65 | $17,800.00 | $5,233.65 |
| 8 | $27,122.07 | $20,200.00 | $6,922.07 |
| 9 | $31,496.67 | $22,600.00 | $8,896.67 |
| 10 | $36,177.50 | $25,000.00 | $11,177.50 |
| 11 | $41,185.98 | $27,400.00 | $13,785.98 |
| 12 | $46,545.06 | $29,800.00 | $16,745.06 |
| 13 | $52,279.27 | $32,200.00 | $20,079.27 |
| 14 | $58,414.88 | $34,600.00 | $23,814.88 |
| 15 | $64,979.98 | $37,000.00 | $27,979.98 |
| 16 | $72,004.64 | $39,400.00 | $32,604.64 |
| 17 | $79,521.03 | $41,800.00 | $37,721.03 |
| 18 | $87,563.56 | $44,200.00 | $43,363.56 |
| 19 | $96,169.07 | $46,600.00 | $49,569.07 |
| 20 | $105,376.96 | $49,000.00 | $56,376.96 |
What is the Compound Interest Calculator?
A compound interest calculator shows how savings grow when returns are reinvested, so you earn returns on both your contributions and prior gains.
How the calculation works
Each period the balance grows by the periodic rate, then your contribution is added. Over time, growth on prior growth (compounding) accelerates the balance.
Example
Starting with $1,000 and adding $200/month at 7% for 20 years grows to roughly $109,000 — far more than the ~$49,000 contributed.
Tips
- Time is the biggest driver — start early.
- More frequent compounding slightly increases growth.
- Consistent contributions matter more than timing the market.
Limitations
Assumes a constant return and does not account for taxes, fees, or inflation.
Frequently asked questions
What is compound interest?
Earning returns on both your principal and previously earned returns, which compounds growth over time.
Compound vs simple interest?
Simple interest is earned only on the principal; compound interest is earned on principal plus accumulated returns.
What is the rule of 72?
Divide 72 by the annual return to estimate the years needed to double your money.
Does compounding frequency matter?
Yes — more frequent compounding produces slightly higher growth for the same nominal rate.
Does this account for inflation?
No — results are in nominal dollars; real purchasing power will be lower.
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Reviewed for the 2025 tax year
See our methodology, data sources, and editorial policy. Educational use only — not financial, tax, or investment advice (disclaimer).