Percentage Calculator
Calculate percentages, increases, and changes easily. Three powerful tools in one.
What is X% of Y?
X is what% of Y?
Percentage Change
Three Calculators
What is X% of Y, X is what% of Y, and percentage change in one tool.
Instant Results
See results update in real-time as you type. No need to click calculate.
Color-coded Results
Percentage changes show green for increase, red for decrease.
Frequently Asked Questions
How do I calculate "X is what % of Y"?
Use the "X is what % of Y" tab. Example: "20 is what % of 80?" → 25%. The formula is: (X ÷ Y) × 100 = percentage. This is useful for understanding proportions.
Why does the result show green or red?
Green (+) means increase, red (-) means decrease. This applies to the "Percentage Change" calculator. For example, going from 100 to 125 is a +25% change. Going from 100 to 75 is a -25% change.
How do I calculate a discount or markup?
For 20% off $100: use "What is X% of Y" → 20% of 100 = $20 discount. For markup, add the result back: $100 + $20 = $120. Or use percentage change from original to new price.
Can I calculate reverse percentage?
Yes! If you know the final amount and percentage, use: Original = Final ÷ (1 + Rate/100). Example: Final $120 includes 20% tax, original = 120 ÷ 1.20 = $100.
About the Percentage Calculator
The percentage calculator answers the three most common percentage questions: what is X% of Y, X is what percent of Y, and what is the percentage change from X to Y.
How to use it
- 1 Pick the type of calculation you need.
- 2 Enter the two numbers.
- 3 Read the answer and the formula used to get it.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30.
How do I calculate percentage change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = a 25% increase.
What is the difference between percentage and percentage points?
Percentage points are the plain difference between two percentages. Going from 10% to 15% is a rise of 5 percentage points, but a 50% increase.