Percentage Calculator

Work out percentages three ways: a percent of a number, what percent one number is of another, and percentage change. Free and private.

What is X% of Y?

Result

X is what percent of Y?

Result

Percentage change from X to Y

Change

How to use

  1. Pick the calculator you need — a percent of a number, what percent one number is of another, or the change between two numbers.
  2. Type your numbers into that row. The result updates as you type, so there is nothing to submit.
  3. Read the answer on the right. Press Calculate any time you want a quick confirmation that everything is up to date.

FAQ

Is anything sent to a server?

No. Every percentage is plain maths done in your browser, so nothing you type is uploaded. The calculator works offline and keeps your numbers private.

How is percentage change worked out?

Percentage change is the difference between the two numbers divided by the starting number, times 100. Going from 200 to 250 is a +25% change; going from 250 to 200 is a −20% change. A positive figure means an increase and a negative figure means a decrease.

What happens if I leave a box empty or use zero?

The result simply stays blank — nothing breaks. Dividing by zero has no sensible answer (for example, asking what percent something is of zero), so that row waits quietly until you enter usable numbers.