Percentage Calculator
Three percentage modes: X% of N, percentage change, and reverse percentage.
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How to use it
- Pick the mode that matches your question: percentage of a number, reverse percentage, or change between two values.
- Fill the two inputs of that mode — the result appears immediately, together with the formula used.
- For percentage change, a negative result means a decrease.
About this tool
Covers the three questions people actually ask: what is X% of N, what percentage one number is of another, and how much a value increased or decreased in percent. Each mode shows the formula used so the result is verifiable, not just a black box.
Your input never leaves the browser: this tool works entirely offline once the page has loaded.
Frequently asked questions
Which of the three modes should I use?
Pick the one that matches your question: "X% of N" scales a quantity, "N is what % of M" compares two values, and "percentage change" measures growth or shrink between two values.
Why does the change mode reject a zero starting value?
Percentage change is relative to the starting point; dividing by zero is undefined, so the tool explains this instead of showing infinity.
Does a negative percentage mean a decrease?
Yes — the result labels the direction automatically, so −20% is displayed as a 20% decrease from the starting value.