Percentage Calculator

The three everyday percentage questions, answered plainly. Everything happens on this page, in your browser — nothing you enter is sent anywhere.

What is X% of Y?

X (%)

of Y

Percentage change

From

X is what % of Y?

of Y

These three shapes cover nearly every percentage question in school life: a discount, a test score out of a total, and whether something grew or shrank between two terms.

How this tool works

Nearly every percentage problem in school and shopping life is one of three shapes: find a percentage of an amount, express one amount as a percentage of another, or measure the change between two amounts. Naming the shape is most of the solution.

Using it, step by step

Decide which of the three questions you are asking — the page is divided by them.
Enter the two numbers the question gives you.
Sanity-check the direction: a percentage increase from 64 to 80 must be bigger than the decrease from 80 back to 64, because the base changed.
For exam questions, write the shape's formula once ('part ÷ whole × 100') and substitute — the habit survives when the page is not in front of you.

Where it stops

Percentage change is not symmetric and is not measured in 'percent points' unless you are comparing two percentages — a rise from 40% to 50% is 10 percentage points but a 25% increase. The calculator reports change relative to the starting value, which is the usual school convention.