About this Compound Interest Calculator
Compound Interest Calculator estimates how an initial amount can grow when interest is added to the balance and future interest is calculated on that updated balance. You can compare annual, semiannual, quarterly, monthly or daily compounding.
Formula or method
Final amount = P × (1 + r ÷ n)^(n × t), where P is principal, r is the annual rate as a decimal, n is compounds per year and t is years.
Example
1,000 at 5% for 2 years compounded monthly grows to about 1,104.94 before taxes, fees or other adjustments.
Common uses
- Compare compound growth with simple-interest estimates.
- Explore how compounding frequency changes a mathematical projection.
- Estimate a future balance from a fixed starting amount and fixed rate.
How to use this tool
- Enter the values or text requested by the calculator.
- Choose units or options when the tool provides them.
- Select the calculation button and review the result.
- Use the formula, example and notes on this page to check whether the result fits your situation.
Important note
This is a mathematical estimate. Real savings, investment or lending products may use fees, taxes, changing rates, different day-count rules or additional deposits and withdrawals.
Estimate only: Money-related results are mathematical estimates. They are not financial, tax, legal, credit or lending advice.
Frequently asked questions
Does this include regular monthly contributions?
No. This version compounds one starting principal and does not add recurring deposits.
Is the result a guaranteed investment return?
No. It is a mathematical estimate based only on the fixed values you enter.