Compound Interest Calculator
Project investment growth with interest, time, and monthly contributions.
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| Year | Balance |
|---|---|
| 1 | 166,510.47 |
| 2 | 236,423.74 |
| 3 | 309,913.9 |
| 4 | 387,163.96 |
| 5 | 468,366.28 |
| 6 | 553,723.07 |
| 7 | 643,446.87 |
| 8 | 737,761.11 |
| 9 | 836,900.64 |
| 10 | 941,112.35 |
What affects compound interest growth
Compound interest means interest can earn additional interest over time. This calculator uses principal, annual rate, time period, and monthly contributions to estimate long-term savings or investment growth.
The result is sensitive to both time and return assumptions, so it is best used for scenario comparison rather than as a guaranteed investment outcome.
Formula or logic
- Future value of a lump sum = Principal × (1 + annual rate)^years
- Regular contributions are accumulated based on when each contribution is made
Example
If the principal is 100,000, the annual return is 5%, and the time period is 10 years, the lump-sum future value is approximately principal multiplied by 1.05 to the 10th power. Monthly contributions increase the result further.
Common questions
Is the result guaranteed?
No. It is a projection based on your inputs. Actual investments may be affected by market risk, fees, taxes, and changing returns.
What rate should I enter?
Use an expected annualized return for a simple scenario. For conservative planning, consider subtracting inflation, fees, or taxes.
Does starting earlier matter?
Under the same return assumption, starting earlier gives money more time to compound, but emergency savings and risk tolerance still matter.
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