Percentage Calculator
Calculate percentages instantly — find X% of Y, what percentage X is of Y, percentage increase/decrease, and reverse percentages.
How to use the Percentage Calculator
Choose your calculation type
"X% of Y" finds a percentage of a number — e.g. 20% of 500 = 100. "What % is X of Y" tells you what percentage one number is of another — e.g. 40 is 20% of 200. "% Increase/Decrease" calculates the percentage change between two values. "Reverse %" works backwards from a value after a percentage was applied.
Practical uses
Use "X% of Y" for discounts and VAT — e.g. 20% of £85. Use "% change" to compare this month's sales to last month's. Use "Reverse %" to find the pre-VAT price when you know the price including VAT. Results include a step-by-step formula breakdown so you can see how the answer was reached.
The word 'percent' comes from the Italian 'per cento' ('out of a hundred'), used in 15th-century Italian trade documents. The % symbol evolved from writing 'per 100' as 'p/100', then 'p%', then just '%'.