Skip to content
Calixo

Compound Interest Calculator

See how your money grows when interest compounds instead of staying simple.

Inputs

%
%

years
years

Saved Scenarios

— select 2+ to compare

Final Amount

$20,097

Interest Earned

$10,097

Spark says

How it's calculated

Formula

A=P(1+rn)ntA = P \left(1 + \dfrac{r}{n}\right)^{nt}
P
— Principal
r
— Annual interest rate
n
— Compounding periods per year
t
— Time in years

What is the Compound Interest Calculator?

Compound interest is interest calculated on both the original principal and the interest already accumulated, so growth accelerates over time rather than staying linear.

How to use it

  1. 1 Enter your starting principal.
  2. 2 Set the annual interest rate.
  3. 3 Choose how often interest compounds.
  4. 4 Set the time period.

Worked examples

$10,000 at 7% for 10 years, compounded monthly

Grows to about $20,097 — more than double, thanks to monthly compounding.

Try it

Advantages

  • •Growth accelerates the longer money is left invested
  • •Rewards starting early over contributing more later

Limitations

  • •Assumes a constant rate — real returns fluctuate
  • •Ignores taxes and fees

Tips

  • 💡 More frequent compounding (monthly vs. annually) meaningfully increases returns over long periods.

Frequently asked questions

How is compound interest different from simple interest?

Simple interest is calculated only on the principal. Compound interest is calculated on the principal plus all interest earned so far, so it grows faster the longer it runs.