What is X percent of Y, calculated online
Percentage calculator: X% of Y, reverse percent, discount and markup. Steps in the result panel.
Pick the mode, type the base and the percent. “What is 18% of 250” is the usual invoice question; the reverse mode answers “50 is what percent of 200”.
Discount subtracts a percent from a price. Markup adds a percent on cost. They are not the same: 20% off 100 is 80; 20% markup on 80 is 96.
VAT inclusive math belongs on the VAT page. This calculator stays on simple percent so the formula stays readable. Overflow on huge inputs is an error, not a wall of digits.
X percent of Y is Y × X / 100. 15% of 80 is 12. A discount of 20% on 250 leaves 200, because you subtract the part rather than multiply by 20. Markup is the other direction: 200 plus 20% is 240. Reverse percent asks what share 12 is of 80, which is 15, not 12. Do not chain rounded percents if you need the original price back: 10% off and then 10% on does not return to the start. This page is the percentage calculator, not the VAT extractor.
FAQ
Compound interest?
No. Use a spreadsheet for compounding. This page is one-step percent.
Discount vs markup?
Discount cuts a selling price. Markup raises a cost. The modes are separate.
Is input uploaded?
No. Arithmetic runs in the browser.