Percentage Calculator
Get your percentage calculated instantly, for free.
The Percentage Calculator handles common percentage calculations — finding what percent one number is of another, calculating a percentage of a value, or finding percentage change between two numbers — in one tool instead of doing the arithmetic by hand.
How to Use
- Choose your calculation type
- Enter your values
- View the calculated result
Frequently Asked Questions
How do I calculate what percentage one number is of another?
Divide the first number by the second, then multiply by 100. For example, 25 is what percent of 200? (25 ÷ 200) × 100 = 12.5%.
How do I calculate a percentage of a number?
Multiply the number by the percentage (as a decimal). For example, 20% of 150 = 150 × 0.20 = 30.
How do I calculate percentage increase or decrease?
Subtract the original value from the new value, divide by the original value, then multiply by 100 — a positive result is an increase, negative is a decrease.
Is this tool free to use?
Yes, completely free with no signup, no limits and no software to install.
Is my data saved anywhere?
No — calculations run in your browser and the values you enter are not stored or sent to a server.
How do I reverse-calculate the original number from a percentage?
If you know that X% of a number equals Y, divide Y by X (as a decimal) to find the original number: Original = Y ÷ (X ÷ 100).
Is this useful for calculating tips or discounts?
Yes — percentage calculations are the basis for tip amounts, discounts, sales tax, and many everyday financial calculations.
What's the difference between percentage points and percent change?
Percentage points measure the raw difference between two percentages (e.g., 40% to 50% is a 10 percentage point increase), while percent change measures the relative change (that same move is a 25% increase relative to the starting 40%).
Can I calculate percentages with negative numbers?
Yes, the same formulas apply — the calculator handles negative values in percentage-of and percentage-change calculations correctly.
Is this useful for calculating grade percentages?
Yes — dividing points earned by points possible and multiplying by 100 is exactly the calculation used for test and assignment grade percentages.
