Summary
Solve common percentage questions and percentage increases or decreases.
Calculation details
The selected mode determines which definition is applied. Calculations retain raw JavaScript number precision; display values are rounded to at most six decimal places.
Formula
X% of Y = (X / 100) × Y; X as a percent of Y = (X / Y) × 100.
Worked example
Percentage Calculator example
20% of 150 is 30.
How it works
Choose whether you need a percentage of a number, a number as a percent of another, or an increase/decrease. Enter only the fields for that mode; unused fields are ignored by validation.
Frequently asked questions
How accurate is the Percentage Calculator?
The calculation keeps raw numeric precision and rounds only the displayed result to at most six decimal places.
What should I do with an invalid result?
Check that every visible value is finite and that no required divisor is zero.