← Compound Interest with Contributions
$1k at 5% for 20 Years
$1,000 grows to $2,713
$1,000 invested at 5% a year for 20 years grows to about $2,713, compounded monthly.
Change the numbers to try your own:
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The compound interest formula
A = P × (1 + r/n)^(n×t) where P = starting amount, r = yearly rate, n = compounds per year, t = years
- Turn the rate into a decimal: 5% = 0.05.
- Tinkkit compounds monthly, so n = 12.
- Raise (1 + r/12) to the number of months and multiply by the starting amount.
- Monthly deposits each grow for the months left after they are added.
Quick reference
| Years | 4% | 6% | 8% |
|---|---|---|---|
| 5 | $12,210 | $13,489 | $14,898 |
| 10 | $14,908 | $18,194 | $22,196 |
| 20 | $22,226 | $33,102 | $49,268 |
| 30 | $33,135 | $60,226 | $109,357 |
Frequently asked questions
How much of that is interest?
About $1,713. Estimate only, not financial advice.
What is the rule of 72?
Divide 72 by the yearly rate to estimate how many years money takes to double: at 6%, about 12 years.
Are returns guaranteed?
No. Investment returns vary year to year. These are estimates, not financial advice.