What is Y% of X?
What percent is X of Y?
What's the percent change from X to Y?
Every Kind of Percentage Calculation in One Place
Work out what a percentage of a number is, figure out what percent one number is of another, or find the increase/decrease rate between two values — three common percentage questions, answered instantly as you type. No app switching, no manual math.
📊 Great For
- Working out a discount price or sales tax amount
- Checking what percent of a test score you got right
- Finding the growth or decline rate between two numbers
- Calculating a tip percentage on a bill
📋 How to Use
- Choose the mode that matches your question at the top
- Enter the two numbers
- The result appears instantly below
- Press "Copy result" to copy it as text
Frequently Asked Questions
What's the difference between the three modes?
"% of a number" answers "what is Y% of X" (e.g. 20% of 200). "X is what %" answers "what percent is X of Y" (e.g. 40 out of 200). "% change" answers "how much did it increase or decrease from X to Y" (e.g. 100 to 120 is +20%).
What happens if I enter 0 as the base number?
A percentage can't be calculated from a base of zero, so the tool shows a warning instead of a result in that case.
Can I enter negative numbers?
Yes, all three modes accept negative numbers and calculate correctly with them.
Why does the % change result show a + or − sign?
A "+" means the value increased and a "−" means it decreased, so you can tell the direction of the change at a glance — for example, 100 → 120 shows +20%.