Answer any percentage question as you type: what is X% of a number, what percent one number is of another, the percentage increase or decrease between two values, a number raised or lowered by a percent, and the whole behind a part.
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This tool answers the everyday percentage questions in one place. Every tab is one question written out as a sentence: take a percent of a number, work out what percent one number is of another, find the whole behind a part, measure the change between two values, or raise and lower a number by a percent.
Each question starts with a small worked example so you can see how it behaves, and every answer has its own copy button. A rounding control under the question sets how many decimal places you get.
Percentage change compares a start value with an end value, so the direction matters. Going from 100 to 120 is a 20% increase, but going from 120 to 100 is a 16.67% decrease, because each change is measured against its own starting point. Percent difference ignores direction. It divides the gap between two values by their average, so 100 and 120 are 18.18% apart no matter which comes first. Use change for a before and after, and difference when neither value is the baseline.
The first three questions are the same relationship seen from three sides: the part equals the percent times the whole. Give any two of those numbers and the third follows. 15% of 200 is 30, so 30 out of 200 is 15%, and if 30 is 15% of something, that something is 200.
For a 20% tip on a 45 bill, the first question gives the tip itself and the increase result gives the total with the tip included. For 30% off an 80 price, the decrease result is what you pay. To undo a percentage, use the find the whole question: if a sale price of 56 is 70% of the original, the original was 80. The same questions cover VAT, raises, interest and test scores.
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