How do I find 20% of a number?

Multiply the number by 0.20 — or use the first calculator above. 20% of 150 is 30.

How is percentage change calculated?

(New − old) ÷ old × 100. Going from 80 to 100 is (20 ÷ 80) × 100 = a 25% increase.

What percent is 45 of 180?

45 ÷ 180 × 100 = 25%. The second calculator does this for any pair of numbers.

Percentage Calculator

The three percentage questions everyone actually asks — answered instantly, with no maths anxiety.

1 · What is X% of a number?

Percent (%)

Of number

—

2 · X is what percent of Y?

Number (X)

Out of (Y)

—

3 · Percentage increase or decrease

From

—

How to use it

Find your question among the three — most percentage problems are one of them.

Type the two numbers.

Press Calculate — done. No formulas to remember.

Percentages in real life

Discounts ("30% off"), exam scores ("45 out of 60"), price rises, salary bumps, battery drain, data usage — daily life is full of percentages, and they are genuinely confusing because the base number keeps changing. A price that rises 25% then falls 25% does not return to the start, and this calculator's change tool shows why: the second percentage acts on a different base. When in doubt, run the numbers here instead of guessing.