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Free percentage calculator for X% of Y, X is what percent of Y, and percent increase/decrease.
“Percentage” covers three different sums that people reach for in the same breath, and mixing them up is where most errors come from. This calculator handles all three, in your browser, with nothing sent anywhere.
Multiply. 18% of 250 is 250 × 0.18 = 45. This is the
tip, the commission, the sales tax.
Divide, then multiply by 100. 45 out of 250 is
45 ÷ 250 × 100 = 18%. This is the test score and the market share.
Difference over the original, times 100. From 250 to 295 is
(295 − 250) ÷ 250 × 100 = 18%. The denominator is the
starting figure, always. Using the ending figure instead is the single most common mistake
in this whole area, and it quietly understates every increase.
If a rate goes from 4% to 6%, that is a rise of two percentage points — and a rise of 50 percent. Both are true and they describe the same change. Headlines pick whichever sounds larger, so it is worth knowing which one you are being shown.
Start at 100. Add 20% and you have 120. Take 20% off that and you have 96, not 100 — because the second 20% is calculated on the larger number. To undo a 20% increase you need a decrease of 16.67%. This is why a stock that falls 50% needs to gain 100% to break even, and it catches people out constantly.
“30% off, then an extra 20% off at the register” is not 50% off. It is
0.70 × 0.80 = 0.56, so you pay 56% of the original — a 44%
discount. Successive percentages multiply; they never add.
Part of the QuikUtil tools collection. Everything is calculated locally in your browser.
Subtract the old value from the new one, divide by the old value, then multiply by 100. From 250 to 295: (295 − 250) ÷ 250 × 100 = 18%. Dividing by the new value instead is the most common error.
A move from 4% to 6% is two percentage points, and also a 50 percent increase. Percentage points measure the gap between two percentages; percent measures the relative change.
No. You end at 96% of the original, because the fall is calculated on the larger number. Reversing a 20% increase takes a 16.67% decrease.
They multiply rather than add. 30% off followed by a further 20% off leaves you paying 0.70 × 0.80 = 56% of the original price, which is a 44% discount, not 50%.
Divide the price you paid by (1 − the discount). $56 after a 44% discount was 56 ÷ 0.56 = $100 originally.
No. The arithmetic happens in your browser. Nothing is uploaded or stored.