Compound Interest Calculator
Shows how a starting amount and regular deposits grow at a given rate, with a year-by-year table.
Final balance
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Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Total deposited —
Interest earned —
Year by year
Reading this —
The formula
A = P(1 + r/n)^(nt) + monthly deposit × ((1 + i)^(12t) − 1) ÷ i i = monthly equivalent rate
Each period earns interest on the balance so far, including earlier interest, so growth speeds up over time.
What to watch out for
- Time matters most. The last years add the most because the balance is largest.
- Compounding frequency matters less than you might expect. Going from yearly to monthly adds little compared with a slightly higher rate.
Frequently Asked Questions
How much will 10,000 grow to in 20 years at 6%?
About 33,102 with monthly compounding and no further deposits. Adding 200 a month takes it to about 125,510.
How often is interest compounded?
It depends on the account: monthly or daily is common for savings. At 6% for 20 years, 10,000 becomes 32,071 compounded yearly and 33,198 compounded daily.