Percentage Calculator

Need to calculate a percentage, work out a percentage change, or find a missing value? This tool covers four common percentage calculations, updating your results as you type. Find the value of a percentage of a number, calculate what percentage one number is of another, work out the percentage increase or decrease between two values, or determine the original number when you know a percentage and its value.

Simply enter the values you know and let the calculator do the rest. All calculations are performed directly in your browser, with nothing sent to a server, keeping your input private and under your control.

What is X% of Y?

What is % of ?

= 30

X is what percent of Y?

is what percent of ?

= 20%

Percentage Change

From to is what change?

= 20% increase

X is Y% of What Number?

is % of what number?

= 150

All four calculators update live as you type, and negative numbers are accepted.

How to use it

The percentage calculator covers the four percentage questions people search for most.

Pick the question that matches yoursEach card is a different type of percentage calculation.
Type your numbersResults update instantly — there's no button to click.
Read the resultEach card shows the answer directly underneath.
Negative numbers work tooUseful for the percentage change calculator when a value has gone down.

Good to know

Nothing is uploaded

Every calculation runs in your browser — nothing is sent to a server.

Order matters for % change

Percentage change is measured from the first number to the second — swap them and the sign flips.

Changing from zero

Percentage change from 0 is undefined, since there's no original amount to compare against.

Frequently asked questions

How do I calculate X% of Y?

Divide the percentage by 100 and multiply by the number. For example 20% of 150 is (20 ÷ 100) × 150 = 30.

How do I calculate percentage change?

Subtract the old value from the new value, divide by the old value, then multiply by 100. A positive result is an increase and a negative result is a decrease.

What's the difference between percentage change and percentage points?

Percentage change is relative (going from 50% to 60% is a 20% increase), while percentage points is the plain difference (a 10 percentage point increase). This calculator works in percentage change, not percentage points.

Can I enter decimals or negative numbers?

Yes, every field accepts decimals and negative numbers.