Percentage Calculator — 3 Calculators in One

X% of Y

X% of Y = ?

Percentage

Of Number

—Result

X is what % of Y

X ÷ Y × 100 = ?%

Value (X)

Total (Y)

—Percentage

% Change

(New−Old) ÷ Old × 100

Original Value

New Value

—Change

About the Percentage Calculator

Percentages are used in everyday life — sales tax, discounts, exam scores, interest rates, statistics, and more. This page offers three separate percentage calculators to cover the most common use cases, all updating in real time as you type.

Calculator 1: X% of Y

Use this to find a percentage of any number. Common uses: calculating a 20% tip on a restaurant bill, finding 15% VAT on a product price, or working out a discount amount in a sale.

Calculator 2: X is what percent of Y

Use this when you have two numbers and need to express them as a ratio. Common uses: your test score as a percentage, market share of a product, or what fraction of a budget has been spent.

Calculator 3: Percentage Change

Use this to measure growth or decline between two values. Common uses: month-on-month sales growth, stock price change, population change, or comparing this year's results to last year's.

Three types of percentage problems

Percentage problems fall into three categories that require different formulas. Knowing which type you are solving prevents common errors.

Find X% of a number — multiply by the percentage as a decimal: 15% of 80 = 80 × 0.15 = 12
What % is X of Y? — divide and multiply: 12 is what % of 80? = 12/80 × 100 = 15%
Find original before % — if 120 is 15% more than X: X = 120 / 1.15 = 104.35
Percentage change — (new - old) / old × 100: from 80 to 92 = (92-80)/80 × 100 = +15%

Frequently Asked Questions

How do I calculate a percentage of a number?

To find X% of Y, multiply Y by X and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30. Use the first calculator on this page to do this instantly.

How do I find what percentage one number is of another?

Divide the first number by the second, then multiply by 100. For example, 30 is what percent of 200? 30 ÷ 200 × 100 = 15%. Use the second calculator on this page.

How do I calculate percentage change?

Subtract the original value from the new value, divide by the original value, and multiply by 100. Formula: ((New − Old) ÷ Old) × 100. A positive result is an increase; negative is a decrease.

What is the percentage increase from 50 to 75?

The percentage increase is ((75 − 50) ÷ 50) × 100 = 50%. Enter these values in the Percentage Change calculator above to verify.

How do I calculate a percentage increase?

(New Value − Old Value) ÷ Old Value × 100. Example: price rises from 80 to 96: (96 − 80) ÷ 80 × 100 = 20% increase. For a decrease: the result is negative. A 20% increase followed by a 20% decrease does not return to the original — 100 → 120 → 96, a net 4% decrease.

How do I work out what percentage one number is of another?

Divide the part by the whole and multiply by 100. What percentage is 45 of 180? = 45 ÷ 180 × 100 = 25%. In a spreadsheet: =A1/B1 formatted as percentage. Common use cases: exam scores (marks/total), budget usage (spent/budget), market share (your sales/total market sales).