Percentage Calculator
Calculate X% of a number, or what percent X is of Y.
Inputs
Allowed range: -1000000 to 1000000
Allowed range: -1000000000 to 1000000000
Results
How it works
Two common questions: 'What is X% of Y?' (X/100 · Y) and 'X is what percent of Y?' (X/Y · 100).
Complete guide
Percentages are everywhere — discounts, tax, tips, grades, interest, statistics. The math behind them is identical: a percent is just a fraction of 100.
The two most common everyday questions are: 'What is X% of a value?' (multiply value by X/100) and 'X is what percent of Y?' (divide X by Y, then multiply by 100). This calculator covers both at once.
Quick mental shortcuts: 10% means move the decimal one place left; 1% means two places left; to add 20% multiply by 1.2; to take 25% off multiply by 0.75. For a tip, doubling the tax (in many U.S. states) lands close to 18–20%.
Frequently asked questions
- How do I calculate a percentage increase?
- Subtract the old value from the new, divide by the old, then multiply by 100. Going from 80 to 100 is (100−80)/80 × 100 = 25% increase.
- What's the difference between percent and percentage points?
- If interest goes from 4% to 6%, that's a 2 percentage point increase but a 50% relative increase. The distinction matters in finance and statistics.
- Can a percentage be over 100%?
- Yes. 150% of 200 is 300. It just means more than the whole.
- How do I reverse a percentage?
- If a price is $120 after a 20% increase, divide by 1.20 to recover the original $100. Don't subtract 20% — that gives the wrong answer.