Percentage Calculator
Three percentage tools in one: percent of a value, ratio as a percent, and percent change.
Calculations run locally in your browser.
What is percentage calculator?
The three most common percentage questions, answered side by side: “What is X% of Y?”, “X is what percent of Y?”, and “What is the percent change from X to Y?”. Results update as you type.
Percent change uses the standard formula (new − old) ÷ |old| × 100, so decreases show as negative values.
How to use it
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Pick the card that matches your question
Each card is one of the three classic percentage problems.
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Enter the numbers
The answer appears instantly below the inputs.
Examples
Tip on a bill
15% of a $200 bill.
15% of 200
Result: 30
Discount as a percent
Paying 75 for something listed at 100.
75 of 100
Result: 75%
Price increase
From 50 to 75.
50 → 75
Result: +50%
Frequently asked questions
As (new − old) divided by the absolute value of old, times 100. A rise from 50 to 75 is +50%; a fall from 75 to 50 is −33.33%.
Percentages of or changes from zero are mathematically undefined, so the tool shows a dash instead of a misleading number.