Percentage Calculator

How to use the percentage calculator

Pick a mode, type two numbers, and the answer appears instantly. Use “% of a number” for a tax or share, “X is what % of Y” to turn a score into a percentage, “% change” to compare an old value to a new one, “± by %” to add or take a percent off a number, “Discount” for a sale price, and “Reverse %” to find the original whole.

How do I work out a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 150 = 150 × 20 ÷ 100 = 30.

How do I calculate a percentage increase or decrease?

Subtract the old value from the new one, divide by the old value, and multiply by 100. A move from 80 to 100 is a 25% increase.

What is the percentage difference between two numbers?

Take the difference between the two numbers, divide by their average, then multiply by 100. (Percentage change instead divides by the original value — use the “% change” mode for that.)

How do I work out a discount or sale price?

Multiply the price by the discount percentage to get the saving, then subtract it. For example, 25% off $80 saves $20, for a $60 sale price — the Discount mode shows both.

How do I increase or decrease a number by a percentage?

Multiply the number by (1 + percent ÷ 100). A 10% increase on 200 is 220; for a decrease, enter a negative percent (−10% gives 180). Use the ± by % mode.

What is a reverse percentage?

It finds the original whole when you know a part and its percentage. If 30 is 20% of a number, divide 30 by 0.20 to get 150 — that's the Reverse % mode.