How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 25% of 200 = (200 × 25) ÷ 100 = 50. Our calculator does this instantly - enter the percentage and the number.

How do I calculate percentage increase or decrease?

Subtract the old value from the new value, divide by the old value, then multiply by 100. For example, going from 80 to 100 is a ((100-80)/80) × 100 = 25% increase.

What percentage is X of Y?

Divide X by Y and multiply by 100. For example, 30 is (30/150) × 100 = 20% of 150.

Percentage Calculator

Three quick calculators for every percentage problem — results appear as you type.

What is X% of a number?

% of = —

X is what percent of Y?

is of —

Percentage increase / decrease

From to = —

How to Use This Percentage Calculator

This page has three separate calculators, one for each common percentage problem. Just type your numbers and the answer appears instantly — no button to press:

X% of a number: e.g. what is 15% of 850? Type 15 and 850 → answer 127.5. Use it for discounts, tips, and tax.
X is what percent of Y: e.g. 45 is what percent of 180? → 25%. Use it for test scores and ratios.
Percentage change: e.g. a price going from 400 to 500 → 25% increase. Use it for price changes, salary raises, and growth rates.

Percentage Formulas Explained

Percentage of a number: (Number × Percent) ÷ 100. What percent: (Part ÷ Whole) × 100. Percentage change: ((New − Old) ÷ Old) × 100 — a positive result is an increase, negative is a decrease. All calculations happen in your browser instantly.

Common Uses

Students use it for grades and exams, shoppers for discount prices during sales, professionals for KPI growth and financial reports, and everyone for splitting bills and calculating tips. Bookmark this page for quick access.

More free tools: Age Calculator · EMI Calculator · Word Counter