Percentage Calculator
Three common percentage calculations in one simple tool.
What is the Percentage Calculator?
This tool covers the three percentage questions people search for most often: finding a percentage of a number, finding what percentage one number is of another, and finding the percentage increase or decrease between two values. Switch between them with the tabs above — each updates its result live as you type.
How to use it
- X% of Y answers "what is 20% of 150?" — useful for tips, discounts and commissions.
- X is what % of Y answers "30 out of 150 is what percent?" — useful for test scores and completion rates.
- % Increase/Decrease answers "what's the percentage change from 80 to 100?" — useful for tracking growth, price changes or performance over time.
Percentage increase or decrease is calculated as (new − old) ÷ old × 100, and shows a negative number when the value has gone down. These three calculations cover the vast majority of everyday percentage questions, from working out a restaurant tip to comparing this month's sales figures with last month's, without needing to remember which formula applies to which situation.
Want the "why" behind this tool? Read The Percentage Mistake Almost Everyone Makes.