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 '%'.
Frequently asked questions
Is the Percentage Calculator free to use?
Yes, the Percentage Calculator is completely free. There is no sign-up, no account required, and no limit on how often you can use it.
How accurate is the Percentage Calculator?
The Percentage Calculator uses standard mathematical formulas and produces results accurate to standard precision. For critical applications, always verify with an authoritative source.
What devices does the Percentage Calculator work on?
The Percentage Calculator works on any device with a modern web browser — desktop, laptop, tablet, or phone. It is mobile-friendly and works offline once the page has loaded.