Percentage Calculator — 3 Calculations in One
Solve every everyday percentage problem in one place. “What's 15% of 2,500?”, “38 is what percent of 190?”, “How much did the price increase from 120 to 156?” — percentages run through discounts, exam scores, taxes, tips, interest rates and growth reports, and mental math gets shaky exactly when the numbers matter. This calculator offers three dedicated modes that update as you type, showing the formula and result for each. Whether you're a student checking marks, a shopper verifying a discount, or a business owner tracking growth, the answer appears instantly — with no signup and complete privacy.
Loading tool…
How to calculate percentages online for free
- 1
Pick the calculation you need: “Percent of a number”, “X is what percent of Y” or “Percentage change”.
- 2
Enter your two numbers in the mode's input fields.
- 3
Read the result instantly, with the full calculation shown beneath it.
- 4
Switch modes anytime — every input updates live as you type.
Why use this percentage calculator tool?
Three essential modes
Percent of a number, reverse percentage (part-to-whole), and percentage increase or decrease — the three calculations covering 95% of daily needs.
Shows its work
Each result displays the formula behind it, so students learn the method while getting the answer.
Live results
Answers update on every keystroke — no calculate button hunting, no page reloads.
Handles decimals & negatives
Decimal inputs and negative change (decrease) are handled correctly, including percentage decreases that trip up mental math.