Best Free Percentage Calculator

Find X% of Y, what percent one number is of another, or the percent change between two values — free.

What is X% of Y?
% of =
X is what % of Y?
is what % of =
Percentage increase or decrease from X to Y
=
X plus or minus Y%
% =
100% free No signup No watermark Files processed in memory, never stored
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How it works

  1. Choose a mode. Select “X% of Y”, “X is what % of Y”, or “% change from X to Y”.
  2. Enter the two numbers. Fill the two fields; the result updates live as you type.
  3. Read the answer. See the result and a plain-language explanation, computed in your browser.

About this tool

Solve the three everyday percentage questions in one place — no signup, nothing sent anywhere. Pick a mode and the two fields relabel for it: find what X% of Y is, work out what percent one number is of another, or calculate the percentage increase or decrease from one value to another. The answer and a plain-language explanation update live as you type. It all runs locally in your browser.

What people use it for

  • Work out a tip, discount or tax as X% of an amount
  • Find what percentage one number is of another
  • Calculate a percentage increase or decrease between two values
  • Check a price change or a test score quickly

Frequently asked questions

Three things: what X% of Y is (e.g. 15% of 80), what percent one number is of another (e.g. 12 is what % of 50), and the percentage increase or decrease from one value to another.

It is the difference between the new and old values divided by the absolute value of the old one, times 100. A positive result is an increase (shown with a +) and a negative one is a decrease.

The two fields stay the same but their relationship differs per mode, so the joining label updates to make the question you are asking clear.

No. Every calculation runs in your browser; the numbers you enter are never uploaded, stored or logged.

When the question would require dividing by zero, the calculator simply waits for valid input instead of showing an undefined result.

Completely free, with no account, no watermark and no limits — it is a client-side tool with nothing to meter.

Yes. It runs in your browser, so Percentage Calculator works on phones and tablets as well as desktop — there is no app to install.

No. Percentage Calculator works with no signup at all; an optional free account only exists to unlock higher usage limits.

Usually just a few seconds for a typical file — Percentage Calculator starts working the moment you give it your input.

Casual use is unlimited, under a generous fair-use cap that keeps it fast for everyone.

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