Every % question · live

🧮 Percentage Calculator

Five everyday percentage questions — type numbers, read the answer instantly: X% of Y, what percent, percent change, increase/decrease and rule of three.

% ofis
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is what % of?
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Fromtochanges by
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% becomes
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Rule of three

goes with, thengoes with
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Numbers accept thousands separators (comma or dot) and decimals. Everything updates as you type; click ⧉ to copy a result. Rule of three: “proportional” scales up together (3 kg → 270k then 7 kg → 630k); “inverse” scales opposite (3 workers → 8 days then 6 workers → 4 days).

Frequently asked questions

How do I find a percentage of a number?
Multiply the base by the percentage and divide by 100. For example 15% of 200 = 200 × 15 / 100 = 30.
How do I compute a percentage increase or decrease?
Percent change = (new − old) divided by old, times 100. Positive means an increase, negative a decrease. From 80 to 100 is (100 − 80) / 80 × 100 = 25%.