Percentage Calculator — % Of, Increase & Decrease
What is X% of Y?
X is what percent of Y?
Percentage change from old to new
About the Percentage Calculator
Three percentage questions cover almost any everyday need: “What is 15% of 80?”, “46 is what percent of 250?” and “What is the percentage change from 90 to 108?” This calculator answers all three at once, live, as you type.
Typical uses include calculating discounts and tips, tax and VAT, exam scores, markup and margin, and growth rates. Each result shows the exact formula used, so you can double-check the arithmetic by hand.
How to use the Percentage Calculator
- Find the section that matches your question: percent of a number, what percent, or percentage change.
- Type your two numbers into that section.
- The answer appears instantly — the other sections keep their own inputs so you can compare scenarios.
Formulas
Part = Percent ÷ 100 × Total Percent = Part ÷ Total × 100 % change = (New − Old) ÷ |Old| × 100
Frequently asked questions
How do I calculate a discount?
Enter the discount as the percent and the original price as the number: “20% of $60” gives the $12 discount; subtract it from the price for the final $48.
Why does percentage change need the absolute old value?
The formula divides by the magnitude of the starting value so that changes measured backwards (from 108 to 90) give the mirror-image −16.7% rather than a nonsensical sign.
Can it handle decimals and negatives?
Yes. All three calculators accept decimals and negative numbers — useful for finance and temperature scenarios.
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