Percentage Calculator
Calculate percentages easily
About the Calculator
Percentages show up in discounts, taxes, grades, and growth rates, but the math can still slow you down. This calculator handles the most common percentage tasks in one place, so you get answers quickly and confidently. Use it to find a percent of a number, to see what percent one number is of another, or to measure change over time. It is useful for shopping, budgeting, or checking statistics at work or school. Instead of guessing or doing mental math, you can verify the exact number in seconds. When the percent is clear, the decision is easier. Use the Percentage Calculator to get a clear result you can act on right away.
Result
50.00
The Formula
How to Calculate Manually
- 1
To find X% of a number: multiply the number by X/100.
- 2
To find what percent A is of B: divide A by B, then multiply by 100.
- 3
To find percentage change: (New - Old) / Old × 100.
- 4
To increase by X%: multiply by (1 + X/100).
- 5
To decrease by X%: multiply by (1 - X/100).
Examples
What is 25% of 200?
200 × 0.25 = 50
50 is what percent of 200?
(50 / 200) × 100 = 25%
What is the percentage change from 100 to 125?
(125 - 100) / 100 × 100 = 25% increase
💡 Tips
- •To quickly find 10%, just move the decimal point one place left.
- •To find 25%, divide by 4. To find 50%, divide by 2.
- •Percentage increase and decrease are not reversible - a 50% decrease followed by 50% increase doesn't return to the original.
- •When comparing percentages, always consider the base number.
🎉 Fun Facts
- •Percentage vs Percentage Points: When unemployment drops from 8% to 6%, that's a 2 percentage point drop but a 25% decrease; confusing these leads to headlines like "unemployment drops 25%!" (technically true but misleading).
- •The 10% Brain Myth: The claim that humans only use 10% of their brains is completely false; brain scans show we use virtually 100% of our brain over the course of a day, with different regions activating for different tasks.
- •Credit Card Math Trap: A $1,000 balance at 18% APR making minimum payments takes 11 years to pay off and costs $1,934 total; the percentage seems small, but compounds to nearly doubling what you owe.
- •The 99% Fat-Free Deception: "99% fat-free" sounds healthy, but 1% fat by weight in a product that's 90% water means the actual fat content is 10% of the dry matter; percentages can be manipulated by what you're measuring.
- •Percentage Increase/Decrease Asymmetry: A 50% price increase from $100 to $150 requires a 33.3% decrease to return to $100 (not 50%); because the base changes, percentage increases and decreases aren't symmetrical.
- •Battery Percentage Lies: Your phone's battery percentage isn't accurate; it's an estimate based on voltage, meaning 20% battery at cold temperatures has less actual power than 20% at warm temperatures.
- •Sales Tax Confusion: A 6% sales tax on a $100 item is $6 (total $106), but if you're given $106 and asked "what was the original price before 6% tax?", it's $100, not $99.94; percentages work differently in reverse.
- •Percentage Change Formula: To calculate percentage change: (New - Old) / Old × 100; so going from 50 to 75 is (75-50)/50 × 100 = 50% increase, not 25%.
- •Probability Percentages: People think 80% chance of rain means "it will definitely rain somewhere" but it actually means "there's an 80% probability of measurable precipitation at any given point"; most misunderstand weather percentages.