Percentage Calculator – 3 Modes, Instant Results
Work out 'X% of Y', 'X is what % of Y', or percentage increase/decrease — all three common cases in one simple tool.
About Percentage Calculator
A percentage calculator handles the three everyday situations: what is X% of Y, X is what percent of Y, and percentage increase or decrease. Our free tool covers all three modes with instant, accurate results — perfect for discounts, tips, taxes, grades and data changes.
📖 The Full Guide
Discounts, tips, taxes, grades, price changes and statistics — learn the three percentage formulas that solve them all, with an instant free calculator.
Read the article →% Percentage Calculator
History
How to Use
Choose a mode: % of, % between, or % change.
Enter the two values.
Click Calculate.
Copy or share the result in one tap.
Frequently Asked Questions
Multiply X by Y and divide by 100. For example, 20% of 150 = 20 × 150 ÷ 100 = 30.
Subtract the old value from the new value, divide by the old value and multiply by 100. A negative result means a decrease.
Yes — every Bostme tool is 100% free, works offline in your browser and never stores your data.
Multiply the price by 0.80 (100% − 20%). Example: $100 × 0.80 = $80. Use our discount calculator for any percentage.
((new − old) ÷ old) × 100. A positive result is an increase, a negative result is a decrease.
The Formula
Percentage of: (X ÷ 100) × Y. Percentage between: (X ÷ Y) × 100. Percentage change: ((new − old) ÷ old) × 100.