Percentage Calculator — % of a Number, Ratio & Change

Answer the three everyday percent questions: what is X% of Y, X is what percent of Y, and the percent increase or decrease between two numbers — results update as you type.

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Examples

What is X% of Y

Input

15% of 200

Output

Multiply: 200 × 0.15 = 30 — useful for tips, tax, and commissions.

X is what percent of Y

Input

30 is what percent of 200

Output

15%

Divide the part by the whole: 30 ÷ 200 = 0.15 = 15%.

How Percentage Calculator works

Percentage Calculator covers the three percentage questions that come up constantly: "what is X% of Y" (a share of a total, like a tip or tax), "X is what percent of Y" (turning a part and a whole into a ratio, like a test score), and "percent change" (how much a value rose or fell between an old and new number). Each mode takes plain numbers and shows the result immediately, so you don't have to remember which value to multiply or divide.

How to use this tool

Pick the type of percentage calculation.
Enter your numbers.
Read the result instantly.

Tips & gotchas

"Percent of" multiplies (X% of Y = Y × X/100); "what percent" divides (part ÷ whole × 100) — pick the mode that matches the value you're missing.
Percentage change always divides by the OLD value, so a rise from 200 to 230 is a 15% increase, not 13%.
A percentage-point change is not the same as a percent change — going from 10% to 12% is +2 points but a +20% increase.
A decrease can't exceed 100% (you can't lose more than all of it), but an increase has no upper limit.

Specifications

Modes	% of a number · part/whole ratio · % change
Change basis	Divides by the original (old) value
Inputs	Any positive or negative number

Features

What is X% of Y
X is what percent of Y
Percentage increase and decrease between two values
Instant results as you type

When to use it

Working out a tip or sales tax as a percentage of a bill.
Converting a test score like 42 out of 50 into a percentage.
Finding how much a price or metric changed month over month.
Splitting a total by a percentage share between people or budgets.

This tool runs in your browser. Your files and text are not uploaded to our servers, and we do not store your input.

Frequently asked questions

How do I find a percentage of a number?+

Use the "X% of Y" mode and enter both — for example 15% of 200 is 30 (200 × 0.15).

How is percentage change calculated?+

It is (new − old) ÷ old × 100, always dividing by the original value. Going from 200 to 230 is a 15% increase; from 230 to 200 is about a 13% decrease.

What is the difference between a percent and a percentage point?+

A percentage point is the absolute gap between two percentages, while a percent change is relative. Moving from 10% to 12% is a rise of 2 percentage points but a 20% increase.