Compound Interest Calculator
Compound Interest Calculator: free, instant and private. Interest on interest is the whole story here.
How the Compound Interest Calculator works
The Compound Interest Calculator takes Principal, Rate (% p.a.), Time (years), Compounding and returns the answer instantly — no button to hunt for, no page reload. Interest on interest is the whole story here. The same rate compounded monthly instead of yearly returns visibly more over ten years, and the gap keeps widening after that.
Enter your own numbers to replace the example values; the result panel updates as you type. Everything runs in this single page, so nothing you enter leaves your device.
Formula used
A = P × (1 + R/n)^(n×T)
| Symbol | Meaning |
|---|---|
| P | principal |
| R | annual rate (%) |
| n | compounding per year |
| T | years |
Interest on interest is the whole story here. The same rate compounded monthly instead of yearly returns visibly more over ten years, and the gap keeps widening after that.
Inputs used: Principal, Rate (% p.a.), Time (years), Compounding.
Worked example
Take the default example — principal of 100000, rate (% p.a.) of 8, time (years) of 5, compounding set to Quarterly:
- Final amount: 148,594.74
- Interest earned: 48,594.74
Frequently asked questions
- What formula does the Compound Interest Calculator use?
- It uses A = P × (1 + R/n)^(n×T), where P is the principal; R is the annual rate (%); n is the compounding per year; T is the years.
- Is the Compound Interest Calculator free?
- Yes. There is no signup, no usage limit and no watermark — the calculator runs entirely in your browser.
- How do I read the result?
- Interest on interest is the whole story here. The same rate compounded monthly instead of yearly returns visibly more over ten years, and the gap keeps widening after that.
- Does the Compound Interest Calculator store or send my data?
- No. Every calculation happens locally in the page, so the numbers you type are never uploaded or logged.
- Does it work on a phone and offline?
- Yes — the page is a single lightweight file that adapts to any screen size. Once it has loaded it keeps working without a network connection.