How this calculator works
A percentage expresses a number as a fraction of 100. It makes different quantities easier to compare, from a discount on a purchase to a change in monthly sales.
The formula
Part = (Percentage ÷ 100) × Whole
Percentage = (Part ÷ Whole) × 100
Change = ((New − Old) ÷ Old) × 100A quick example
20% of 500 is (20 ÷ 100) × 500 = 100. If a price rises from 100 to 120, the increase is 20%.
How to use this calculator
- Choose the type of percentage calculation.
- Enter the two values in the labeled fields.
- Select Calculate to see your result.
A few common questions
Can a percentage be more than 100%?
Yes. 150% of a value is one and a half times that value.
What is the difference between percentage and percentage points?
A rate moving from 10% to 15% rises by 5 percentage points, which is a 50% relative increase.
Why can I not calculate a change from zero?
Percentage change divides by the original value. Division by zero is undefined, so use an absolute difference instead.
Can I use negative numbers?
Negative values are accepted for parts and percentages. Percentage change requires a positive starting value to avoid an ambiguous interpretation.