Percentage calculator
Find a percent of a number, what percent one number is of another, percent change, or a number increased or decreased by a percent.
When you want a share, what percent something is, or a percentage increase or decrease.
The formulas are Y×X÷100, X÷Y×100, (B−A)÷|A|×100, and Y×(1±X÷100). This is not a discount, tax, or tip tool.
What this page does
It finds X percent of a number, what percent one number is of another, the percent change from A to B, and a number increased or decreased by X percent. Discount, tax, tip, and compound interest are not part of this page.
Formulas
X% of Y is Y × X ÷ 100.
X as a percent of Y is X ÷ Y × 100. If Y is 0, nothing is calculated.
Percent change from A to B is (B − A) ÷ |A| × 100. If A is 0, nothing is calculated.
Increasing Y by X% is Y × (1 + X ÷ 100). Decreasing it is Y × (1 − X ÷ 100).
Examples
15% of 200 is 30. 30 is 15% of 200. 80 to 100 is +25%, and 100 to 80 is −20%. Increasing 100 by 20% gives 120, and decreasing it by 20% gives 80.
Decimals, negatives, and zero
Decimals and negative numbers are allowed. Zero is allowed unless the formula divides by zero. A result that is not a finite number is refused. The numbers you type and the result are not sent for measurement.
Questions
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. If the whole is 0, nothing is calculated.
How is a percentage increase or decrease different?
A larger second number is a positive change. A smaller one is negative. If the starting number is 0, nothing is calculated.
Are the numbers sent anywhere?
The calculation stays on this device. The inputs and the result are not sent for measurement.