Calculate percentages instantly
Our free percentage calculator handles all the common percentage calculations you encounter daily. Whether you are figuring out a discount, calculating tax, or comparing values, this tool gives you instant answers. It supports four calculation modes: finding a percentage of a number, determining what percentage one number is of another, calculating percentage change between two values, and finding the percentage difference.
Each mode displays the formula used so you can understand the math behind the result. Results update instantly as you type, making it fast and efficient. This is especially useful for students, shoppers calculating discounts, business professionals analyzing data changes, and anyone who needs quick percentage computations without the hassle of manual math. All calculations happen in your browser with zero server processing, ensuring your data stays private.
A percentage calculator answers the four everyday percent questions: what is X% of Y, X is what percent of Y, percentage increase or decrease, and the original value before a percentage change.
Each mode uses one small formula, shown alongside the answer so you can check the working. SnoopTool computes locally and instantly, with no rounding surprises.
| X% of Y | Y × X ÷ 100 |
|---|---|
| X is what % of Y | X ÷ Y × 100 |
| Percentage change | (new − old) ÷ old × 100 |
| Reverse a % increase | original = new ÷ (1 + rate ÷ 100) |
| Percentage point | A change from 10% to 12% is +2 percentage points, but a +20% relative change |
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