Percentage Calculator
Find X% of a number, what percent X is of Y, and percentage change.
How to use
- Choose what you want to calculate from the dropdown.
- Enter your two numbers.
- The answer appears instantly - no button needed.
Frequently asked questions
How do I calculate a percentage change?
Percentage change = (new − old) ÷ old × 100. Pick “Percentage change from X to Y” and enter both values.
How do I find what percent X is of Y?
Divide X by Y and multiply by 100. Choose the second mode and enter both numbers.
Every kind of percentage question, solved
Percentages come up constantly and trip people up just as often. This calculator handles the three common forms in one place: what is X% of a number, what percent one number is of another, and the percentage increase or decrease between two values. Tips, discounts, tax, test scores, commission, price changes - enter the numbers and read the answer, no formula-hunting required.
The three calculations, in plain terms
'X% of Y' scales a number - 15% of a $80 bill is $12 of tip. 'X is what percent of Y' expresses a ratio - scoring 42 out of 50 is 84%. 'Percentage change' measures movement between two values - a price going from $200 to $250 is a 25% increase. That last one is where mistakes hide: percentage change always divides by the starting value, so a rise from 200 to 250 (up 25%) and a fall from 250 to 200 (down 20%) are not symmetrical, even though the dollar gap is identical.
Percentage points vs. percent
One distinction worth keeping straight: a rate moving from 5% to 7% is a rise of 2 percentage points, but a 40% increase in the rate itself - news headlines routinely blur the two. For money-specific versions of these calculations, our Discount Calculator handles sale prices, the Tip Calculator splits a bill with gratuity, and the GST, VAT and Sales Tax calculators add or extract tax at a given rate. This general percentage tool is the one to reach for when the question isn't tied to a specific domain.