About this percentage calculator
Find a percentage of a number, express one number as a percentage of another, or measure a percentage change. Choose the mode that matches your question, then enter the two values. This is useful for discounts, progress reports, scores, and comparisons. Results use ordinary arithmetic and remain in your browser. The labels explain the role of each number so you can check your calculation before using it.
How the percentage calculator works
Percentage of: A × B / 100. A as a percentage of B: A / B × 100. Change from A to B: (B − A) / |A| × 100.
Percentage Calculator examples
20% of 150
30
Change from 80 to 100
25%
Limitations & privacy
A zero denominator has no defined percentage. Negative starting values use an absolute denominator for change. Results are displayed to two decimal places.
Inputs and results stay in this browser. Only tool identifiers are stored for your recently used tools. You can clear that history from the directory.
Percentage Calculator: frequently asked questions
Can I use decimal percentages?
Yes, values such as 12.5 are supported.
Why is changing from zero rejected?
Percentage change divides by the starting value, and division by zero is undefined.
Is a percentage-point change the same?
No. Moving from 20% to 30% is 10 percentage points and a 50% relative increase.
Updated September 20, 2026