Percentage Calculator

Three percentage calculations in one place: a percentage of a number, one number as a percentage of another, and the percentage increase or decrease between two values. Each result shows how it was worked out.

Percentage of a number = number × percentage ÷ 100. Percentage change = (new − old) ÷ old × 100.

Options

• Three calculations: a percentage of a number, one number as a percentage of another, and percentage change.
• The working is shown with every result.

Limits

• Numbers take up to two decimal places. The percentage takes up to four and runs from 0 to 1000.
• Results are rounded to two decimal places.
• A percentage change cannot be worked out when the old value is zero.
• Negative values are accepted for the base number and for both values of a change. A change is divided by the absolute old value.

Privacy

The numbers are calculated in your browser and are not sent to any server.

Questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30.

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

Divide the number by the total and multiply by 100. For example, 30 out of 120 is 25%.

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. From 80 to 100 is a 25% increase, and from 100 to 80 is a 20% decrease.

Why is the increase not the same as the decrease between the same two numbers?

Each percentage is divided by its own starting value. From 80 to 100 divides by 80, and from 100 to 80 divides by 100.