How to use the compound interest calculator
Compute the future value of an investment with compounding. Enter principal, annual rate, compounds per year, years in the fields above; the future value, interest earned are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- P — Principal
- r — Annual rate (%)
- n — Compounds per year
- t — Years
Worked example
With principal = 1000, annual rate = 5 %, compounds per year = 12, years = 10, the calculator gives future value ≈ 1,647.009; interest earned ≈ 647.0095.
Frequently asked questions
What is the formula for the compound interest calculation?
Future value = P × (1+r / 100 / n)^(n × t). Interest earned = [Future value]-P. Here P is principal, r is annual rate (%), n is compounds per year, t is years.
What inputs do I need for the compound interest calculator?
You need principal, annual rate in %, compounds per year, years. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.