Percentage Calculator
Find percentages, increases, decreases, and what one number is of another. Compare a part with a whole, measure a change, or raise and lower a number by a percent.
Worked examples
Example 1
20% of 250
Convert 20% to 0.20, then multiply by 250. The result is 50.
Example 2
45 is what percent of 180?
Divide 45 by 180 to get 0.25, then multiply by 100. The result is 25%.
Example 3
From 100 to 125
The difference is 25. Dividing by the absolute original value, 100, gives a 25% increase.
Common questions
How is percentage change calculated from a negative starting value?
The change is the new value minus the original value, divided by the absolute value of the original, then multiplied by 100. Moving from -100 to -50 is a 50% increase because the value rose by 50 relative to a starting magnitude of 100.
Why is percentage change undefined when the original value is zero?
The formula divides by the original value. Division by zero has no numeric result, so a change that starts at zero cannot be expressed as a percentage.
Can the calculator use decimals and negative numbers?
Yes. Enter values such as 12.5 or -40. A negative percent of a positive number is negative, and decreasing a number by more than 100% produces a negative result.