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iyziTool

Percentage Calculator

Four percentage calculations in one tool: find a percentage of a value, express one number as a percentage of another, measure change between two figures, or apply a markup or discount.

Result
30

About this tool

Percentage change is the calculation people get wrong most often, because increase and decrease are not symmetric. A price that rises 50% then falls 50% does not return to its starting point — it ends 25% lower.

Use 'X% of Y' for VAT, tips and commissions; 'X is what % of Y' for conversion rates and shares of a total; '% change' for growth between two periods; and 'Add X% to Y' for markups and discounts, entering a negative percentage to subtract.

Frequently asked questions

How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. 15% of 200 is 0.15 × 200 = 30.
How do I work out percentage increase?
Subtract the old value from the new one, divide by the old value, then multiply by 100. From 80 to 100 is (100 − 80) ÷ 80 × 100 = 25%.
How do I remove VAT from a total?
Divide by 1 plus the rate. For 20% VAT, divide the gross amount by 1.2 to get the net amount.
Why doesn't a 50% rise then a 50% fall return to the start?
Each percentage applies to a different base. 100 rises to 150, then 50% of 150 is 75 — so you finish 25% below where you started.
What is the difference between percent and percentage points?
Going from 10% to 12% is a rise of 2 percentage points, but a 20% relative increase. Mixing the two is a common source of misleading statistics.

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