How is percentage change calculated?

Percentage change = ((new - old) / old) × 100. A positive result means an increase; negative means a decrease. For example, from 80 to 100 is a 25% increase.

What if I divide by zero?

If Y is 0 in 'X is what % of Y?' or P is 0 in '% change', the result will be Infinity or NaN. Enter non-zero denominators for valid results.

Does it support decimal inputs?

Yes. All input fields accept decimal values.

Is my data sent to a server?

No. All calculations run in your browser. Nothing is transmitted.

Percentage Calculator

Three percentage calculators in one: A% of B, X is what % of Y, and % change from P to Q.

How to use this tool

1Fill in the values for the calculation you need — each panel is independent.
2'What is A% of B?' — enter A and B.
3'X is what % of Y?' — enter X and Y.
4'% change from P to Q' — enter the original value (From) and new value (To).

About Percentage Calculator

Percentage calculations come in three distinct forms that people confuse constantly. This tool provides all three in separate panels. 'What is A% of B?' computes (A/100) × B — useful for calculating a 15% tip on a $60 bill or a 20% discount on a price. 'X is what % of Y?' computes (X/Y) × 100 — useful for finding what percentage 45 is of 180, or what share of a budget one item represents. '% change from P to Q' computes ((Q-P)/P) × 100 — useful for calculating revenue growth, price changes, or weight loss percentages. Results are shown to 4 decimal places with trailing zeros removed. All three calculators update in real time as you type. Runs entirely in your browser.

Frequently asked questions

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