Percentage calculator
Calculate a percentage, a share or a % change.
- Instant
- Free
- Private (processed locally)
- No sign-up
The three most useful percentage calculations
A percentage expresses a proportion out of 100. Three questions come up constantly: “what is X% of Y?”, “what percentage of Y is X?” and “what is the % change between two values?”. This tool handles all three at once, live.
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X% of a number
For a discount, a deposit or VAT: enter the rate and the amount.
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A share as a percentage
For a grade or a proportion: enter the part and the total.
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A % change
For a price or salary increase: enter the start and end values.
Real-world examples
- Sales: an item at $80 with −30% costs 80 − (80 × 30 ÷ 100) = $56.
- Tip: 15% of $45 = $6.75.
- Increase: going from $1,500 to $1,650 is a +10% change.
All calculations run in your browser, with no data sent anywhere.
Frequently asked questions
How do I calculate X% of a number?
Multiply the number by the percentage, then divide by 100. Example: 20% of 150 = 150 × 20 ÷ 100 = 30.
How do I find what percentage a number represents?
Divide the part by the total, then multiply by 100. Example: 30 out of 150 = 30 ÷ 150 × 100 = 20%.
How do I calculate a percentage increase or decrease?
Use (final value − initial value) ÷ initial value × 100. A positive result is an increase, a negative result a decrease.
What is a percentage calculator used for?
Discounts and sales, tips, VAT, grades and averages, interest, price changes, statistics… Percentages are everywhere in daily life.