Check everyday percentage maths with visible formulas, strict input validation and clear reference bases.
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A percentage is a fraction expressed out of 100. To find X% of Y, divide the percentage by 100 and multiply by the value: (X ÷ 100) × Y. For example, 20% of 500 is (20 ÷ 100) × 500 = 100. This percentage calculator runs that formula the instant you type, and covers five more everyday calculations so you rarely need to reach for a formula sheet.
X% of Y — the core operation above. Enter a percentage and a base value to get the portion. Useful for VAT, sales tax, deposits, and interest estimates.
X is what % of Y — turns two numbers into a percentage: (X ÷ Y) × 100. If 50 of 200 students passed, that is (50 ÷ 200) × 100 = 25%. Handy for test scores, survey shares, and progress tracking.
Percentage change — measures growth or decline relative to the magnitude of the original value: ((new − old) ÷ |old|) × 100. Going from 100 to 150 is a +50% increase; from 150 to 100 is a −33.33% decrease. A zero original has no defined percentage change.
Discount — shows the final price and the amount saved for one discount between 0% and 100%. A 25% discount on 1,000 gives 1,000 − 250 = 750, saving 250. Apply multiple discounts one at a time because each uses the latest reduced price.
Tip split — adds a tip percentage to a bill and divides the total across a group. A 10% tip on 5,000 makes the total 5,500; split three ways that is about 1,833 each.
Margin / markup — the two most confused business percentages. Margin is profit as a share of the selling price: ((sell − cost) ÷ sell) × 100. Markup is profit as a share of the cost: ((sell − cost) ÷ cost) × 100. A cost of 600 sold for 1,000 gives a 40% margin but a 66.67% markup — the same profit, two different reference points.
Reversing a percentage change does not return the original: a value that rises 50% must then fall 33.3% (not 50%) to come back. A 20% discount followed by a further 10% off is not 30% off — the second cut applies to the already-reduced price. And when comparing prices or margins across markets, always keep the reference base consistent. Every result on this page shows the underlying figures so you can check the reasoning at a glance.