Compound Interest Calculator
What money grows to with compound interest, compounded daily, monthly or yearly, with a deposit every month.
What $10,000 grows to with interest compounded monthly
| Rate | 5 years | 10 years | 20 years | 30 years |
|---|---|---|---|---|
| 3% | $11,616 | $13,494 | $18,208 | $24,568 |
| 4% | $12,210 | $14,908 | $22,226 | $33,135 |
| 5% | $12,834 | $16,470 | $27,126 | $44,677 |
| 7% | $14,176 | $20,097 | $40,387 | $81,165 |
| 10% | $16,453 | $27,070 | $73,281 | $198,374 |
How often interest compounds: $10,000 at 5% for 10 years
| Compounded | Balance | Interest | APY |
|---|---|---|---|
| Daily | $16,487 | $6,487 | 5.127% |
| Monthly | $16,470 | $6,470 | 5.116% |
| Quarterly | $16,436 | $6,436 | 5.095% |
| Twice a year | $16,386 | $6,386 | 5.062% |
| Yearly | $16,289 | $6,289 | 5.000% |
Saving a fixed amount every month, at 5% compounded monthly
| Each month | 10 years | 20 years | 30 years |
|---|---|---|---|
| $100 | $15,528 | $41,103 | $83,226 |
| $250 | $38,821 | $102,758 | $208,065 |
| $500 | $77,641 | $205,517 | $416,129 |
| $1,000 | $155,282 | $411,034 | $832,259 |
How this calculator works
Compound interest earns interest on the interest already added. With a rate r compounded n times a year, a sum P grows to P × (1 + r/n)^(n × t) after t years.
Monthly deposits are added at the end of each month. So that deposits and compounding line up whatever the schedule, the calculator uses the monthly rate that is equivalent to your compounding: (1 + r/n)^(n/12) − 1. For daily and monthly compounding that is exact; for quarterly or yearly it credits deposits their share of interest within the period.
What it assumes
- The rate stays the same for the whole period.
- No withdrawals, fees or taxes. Interest in a taxable account is taxed each year, which slows growth.
- For investments, the rate is an average: real returns vary from year to year.
Questions people ask
How much will $10,000 grow in 10 years with compound interest?
At 5% compounded monthly, $16,470. At 7%, $20,097. The first table above has more rates and periods.
What is the compound interest formula?
A = P(1 + r/n)^(nt), where P is the starting amount, r the yearly rate as a decimal, n the number of times it compounds a year and t the number of years.
Is daily compounding much better than monthly?
Only slightly. At 5%, daily compounding gives an APY of 5.127% against 5.116% monthly: $17 more on $10,000 over 10 years. The rate matters far more than the schedule.
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. The exact answer at 6% compounded yearly is 11.9 years.
What is the difference between simple and compound interest?
Simple interest is paid only on the original amount; compound interest is also paid on interest already earned. $10,000 at 5% simple interest earns $5,000 in 10 years; compounded yearly it earns $6,289.
How do I compare accounts that compound differently?
Compare APY, not the interest rate: APY already includes compounding, and banks must quote it on deposit accounts. The APY calculator converts between the two.
Terms explained
Related calculators
Sources
- Investor.gov (SEC): Compound interest calculator and explanation
- CFPB: Regulation DD, Appendix A (annual percentage yield)
Updated by the RateHerald team. The maths is tested against worked examples; report a problem.