See how your money grows — with compound interest
Calculate daily, weekly, monthly or annual compounding. Add monthly contributions. See your exponential growth point. Free, no sign-up.
| Period | Balance | Total Contributions | Interest This Year | Total Interest |
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What is compound interest?
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. Unlike simple interest, it grows exponentially — the longer you leave money compounding, the faster it grows.
The Rule of 72
Divide 72 by your annual interest rate to estimate how many years it takes to double your money. At 7%, your money doubles in approximately 10.3 years.
Compounding frequency matters
Daily compounding earns slightly more than monthly, which earns more than annual. The difference grows larger over longer time periods.
Monthly contributions accelerate growth
Adding even small regular contributions dramatically increases the final balance. Each contribution starts its own compounding cycle immediately.
Time is the most powerful variable
Starting 10 years earlier can double your final balance. This is why financial advisors emphasize starting as early as possible.