Percentage Calculator
Three modes for the percentage questions you actually ask.
Inputs
Result
Visual breakdown
Formula
% of = (P/100) × V · is what % = (X/Y) × 100 · increase = V × (1 + P/100).
Example
20% of 150 = 30. 20 is 13.33% of 150. 150 increased by 20% = 180.
Related: Discount · Percent change · Sales tax
How to use
- Pick the mode that matches your question: % of, is what %, or increase by %.
- Enter the two numbers — order matters for “is what %”.
- Read the answer; toggle modes to compare the same numbers different ways.
When it's useful
- Working out a tip, discount, sales tax or markup.
- Converting a fraction (X out of Y) into a percentage.
- Estimating a price after a percent increase or decrease.
- Checking grades, scores or progress against a total.
Common examples
Common answers
- What is 20% of 50?10.
- What is 15% of 200?30.
- 25 is what percent of 200?12.5%.
- Increase 80 by 25%?100.
- Decrease 80 by 25%?60.
- How do I add a percent to a number?Multiply by (1 + percent/100). For 12% on 250: 250 × 1.12 = 280.
Embed this calculator
Free · noindex iframeAdd this calculator to your site. Copy the snippet — it works on any page with a simple iframe.
Frequently asked
How do I find what percent X is of Y?
Use the “is what %” tab. Enter X (the part) and Y (the whole).
Does it support negatives?
Yes — negative percents work and produce a decrease.
What if the whole is zero?
Dividing by zero is undefined, so the result is blank.
How do I calculate a percent change between two numbers?
Use the Percent Change Calculator: (new − old) ÷ old × 100. A drop from 200 to 150 is −25%.
How do I calculate a discount?
Discount amount = price × (% ÷ 100). For sale price use the Discount Calculator, which handles tax too.
Why isn't 50% off twice the same as 100% off?
Stacked percents apply to the new total each time. 50% off then 50% off again leaves 25% — not 0%.