Percentage Calculator
Work with percentages in three ways: find what X% of a number is, find what percent one number is of another, or apply a percentage increase or decrease to a value. All calculations run in your browser and update as you type.
Calculate percentage
Enter values to find percentage.
How it works
What is X% of Y? Result = (X/100) × Y. Example: 20% of 150 = 0.20 × 150 = 30.
X is what % of Y? Result = (X/Y) × 100. Example: 30 is (30/150)×100 = 20% of 150.
X increased/decreased by Y%: Result = X × (1 ± Y/100). Example: 100 increased by 15% = 100 × 1.15 = 115; 100 decreased by 10% = 100 × 0.90 = 90.
When to use it
Use this for tips, discounts, margins, test scores, or any situation where you need to compute or interpret a percentage. It avoids mental math errors and gives exact results.
Frequently asked questions
- How do I find what percent X is of Y? Divide X by Y and multiply by 100. So (X/Y)×100 gives the percentage. Use the second mode in this calculator.
- What is percentage increase? Increase = ((New − Old) / Old) × 100. It measures how much a value went up relative to the original.