See each period's growth
Principal + Interest split
Rate, time, frequency
Earned vs contributed
Enter your parameters and click "Calculate" to see the breakdown.
| Year | Starting Balance | Contributions | Interest Earned | Ending Balance |
|---|
Compound interest is when you earn interest on both your original investment AND on previously earned interest. This creates exponential growth over time.
Thanks to compounding, starting 10 years earlier can double your final amount.
// $10,000 at 7% for 30 years:
// Result: $76,123
// Same amount for 40 years:
// Result: $149,745 (almost 2x!)
// Time amplifies returnsMonthly compounding beats annual compounding, especially at higher rates.
// $10,000 at 12% for 10 years:
// Annual: $31,058
// Monthly: $33,004 (6% more!)
// Choose monthly when availableDivide 72 by your interest rate to estimate how many years it takes to double your money. At 8% return, your money doubles in approximately 72/8 = 9 years.
Simple interest is calculated only on the principal. Compound interest is calculated on principal plus accumulated interest, leading to exponential growth over time.
Continuous compounding uses the formula A = Pe^(rt) where e �?2.71828. It represents the theoretical maximum growth and is slightly higher than daily compounding.