Percentage Calculator
Four fast percentage modes: find X% of Y, compare values, calculate change, or add/subtract a percent.
The Percentage Calculator bundles the four percentage questions people ask every day into one fast tool: What is X% of Y? A is what percent of B? What is the percent change from A to B? And how much is A after adding or subtracting a percentage?
Percentages show up everywhere — tips and discounts, sales tax and VAT, pay raises and price increases, test scores, interest rates, margins and statistics. Instead of remembering which decimal to move or which formula to use, just pick the mode, type your numbers, and read the exact answer with the working shown underneath.
The tool runs entirely in your browser with instant results as you type, and it handles decimals and large numbers cleanly. Percent-change mode tells you whether the movement was an increase or a decrease, so there is no ambiguity about the sign.
Result
30
15.00% of 200
How to use the Percentage Calculator
- Choose the type of calculation you need from the dropdown.
- Fill in the values for that mode (for example, X% of Y, or the two numbers for a percent change).
- Read the result instantly — the sub-line shows the exact relationship being calculated.
- Switch modes to cross-check the same numbers from another angle, for example verifying a discount with the 'add/subtract' mode.
Frequently asked questions
How do I calculate X% of Y?
Multiply Y by X and divide by 100: X% of Y = Y × X ÷ 100. For example, 15% of 200 = 200 × 15 ÷ 100 = 30. This tool does that instantly in its first mode.
How do I work out the percent change between two numbers?
Subtract the starting value from the ending value, divide by the starting value and multiply by 100: (B − A) ÷ A × 100. A positive result is a percentage increase and a negative result is a decrease. The calculator reports the direction automatically.
Is 'A is what percent of B' the same as percent change?
No. That mode asks how big A is relative to B as a single comparison: A ÷ B × 100. Percent change instead measures the movement from one value to another. For example, 50 is 25% of 200, but changing 50 into 200 is a 300% increase.
Can I use it for adding sales tax or subtracting a discount?
Yes — use the fourth mode, 'Add or subtract a percent'. Enter a negative percent to subtract (like a 20% discount) or a positive one to add (like an 8% sales tax), and it returns the final value plus the difference.
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