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About this tool
Compound interest earns interest on both the starting principal and previously added interest. Compare compounding frequencies and time periods with a fixed annual rate.
How to use it
- Enter the starting amount and annual rate.
- Enter the number of years.
- Choose a compounding frequency and calculate.
Compound interest formula
Future value = P × (1 + r ÷ n)⁽ⁿᵗ⁾
P is principal, r is the annual rate as a decimal, n is compounding periods per year, and t is years.
Worked example
Good to know
This calculator assumes a constant rate. Real investments can change in value and may lose money. The result is not financial advice.
Need more explanation or examples?
Read about interest rates and repayment calculations →Frequently asked questions
What does monthly compounding mean?
Interest is added twelve times per year.
Does more frequent compounding increase the result?
With the same nominal annual rate, more frequent compounding usually gives a slightly higher future value.
Does this include regular deposits?
No. This version calculates growth from one starting amount.
Tool logic and explanatory wording reviewed on July 19, 2026.