Percentage Calculator
Work out percentages and percent change.
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📝 About Percentage Calculator
The Percentage Calculator answers the three percentage questions people ask most often, each in its own box with an instant result: what is X% of Y, X is what percent of Y, and what is the percent change from X to Y.
Use it to work out a discount (20% off 45,000), a tip or commission, a test score as a percentage, the share of a budget spent so far, or how much sales, prices or subscribers grew or shrank between two periods.
The formulas are simple. X% of Y is (X ÷ 100) × Y. X as a percentage of Y is (X ÷ Y) × 100. Percent change is (new − old) ÷ old × 100, so a positive result means an increase and a negative one a decrease. A common mistake is mixing up percent change with percentage points: a rate that rises from 3% to 4% has gone up by one percentage point, but by about 33.3% in relative terms. Results are rounded to three decimal places, and a dash appears when a value cannot be calculated, for example when dividing by zero.
📘 How to use
- 1
Pick the right box
Choose the box that matches your question among the three calculation types.
- 2
Enter two numbers
Type the X and Y values into the two input fields of that box.
- 3
Read the result
The answer updates instantly on the right as you type.
❓ FAQ
How do I calculate a discounted price?
Use the first box to find the discount amount (e.g. 20% of 45,000 = 9,000), then subtract it from the original price.
Why is my percent change negative?
A negative result means the value decreased from X to Y. For example, going from 100 to 80 is a −20% change.
What is the difference between % and percentage points?
Percentage points measure the plain difference between two rates, while percent change is relative. From 3% to 4% is +1 percentage point but about +33.3%.