Percentage Calculator

Three common percentage problems, solved instantly.

How to use this calculator

Enter a percent and a number to find 'X% of Y', or enter two numbers to find the percentage change between them.

What the result means

Percentage change tells you how much something moved relative to its starting value — the standard way to describe price moves, returns and growth.

How the percentage math works

Percent means "out of 100". To find X percent of a number you multiply the number by X and divide by 100 - for example, 15% of 200 is 200 x 15 / 100 = 30. The other modes answer the reverse questions: what percent A is of B (A/B x 100), and the percentage change from A to B ((B-A)/A x 100).

Worked examples

Finding a discount: 25% off a $120 item is $120 x 0.25 = $30, leaving $90. Percentage change: if rent goes from $1,000 to $1,150, that is a 15% increase. Knowing which mode you need is half the battle - this tool does all three.

Where people get it wrong

Percentage points and percent are not the same: a rate rising from 5% to 6% is a 1 percentage-point increase but a 20% increase. When comparing growth rates, always ask "20% of what?" before trusting the number.

Frequently asked questions

How do I calculate percentage change?

Subtract the start from the end, divide by the start, and multiply by 100.

Is a 50% drop the same as a 50% rise?

No — a 50% drop needs a 100% rise to recover, because they're calculated on different bases.

Why does a 50% increase need a 33% decrease to return?

Because percentages act on the current total. $100 up 50% is $150; returning to $100 needs a $50 drop, which is one third of $150.