What is a percentage?
A percentage is a way to describe a number as parts per hundred. It makes comparisons faster and gives a clear view of discounts, growth, proportions, and share of a total.
25%
Means 25 out of 100.
50%
Means half of the whole.
100%
Means the entire amount.
How to use this calculator
Choose a mode
Pick the question you want to answer: part of a whole, percent of a number, or reverse calculation.
Enter the values
Type the percentage and base value, or load one of the example inputs.
Copy or save the result
The calculator shows the output instantly and can copy the inputs plus result in one click.
Formula and worked example
The standard formula is simple: multiply the percentage by the value, then divide by 100.
Percentage Value = (X / 100) × Y
Example
What is 20% of 500?
(20 / 100) × 500 = 100
Where percentages are useful
Shopping
Calculate discounts and final prices quickly.
School & exams
Convert marks into percentages and compare scores.
Finance
Work out tax, interest, margins, and growth rates.
Health
Track ratios used in body composition and nutrition.
Why use an online percentage calculator?
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Frequently Asked Questions
Using an online percentage calculator is the fastest and most reliable method.