Free Online Percentage Calculator
Percentages show up everywhere — discounts, tax rates, exam scores, profit margins, tipping, and more. Yet the mental math can trip anyone up, especially when calculating percentage change or working backwards from a final number. Our free percentage calculator handles all the common percentage calculations instantly, so you never have to second-guess your math again.
Whether you need to figure out what 15% of 250 is, calculate the percentage change between two numbers, or determine what percentage one number is of another, this tool gives you the answer in real time.
How to Use the Percentage Calculator
Enter your numbers into the input fields and the result calculates automatically. You can solve problems like "What is X% of Y?", "What percentage is X of Y?", and "What is the percentage change from X to Y?" Just fill in the values you know and the calculator solves for the unknown. Results update in real time as you type.
Why You Need a Percentage Calculator
- Shoppers calculate sale prices and discounts before buying.
- Students convert test scores and determine grade percentages.
- Business owners calculate profit margins, markups, and revenue changes.
- Accountants compute tax rates, interest amounts, and financial ratios.
- Fitness enthusiasts track body fat percentage changes and calorie breakdowns.
Key Features
- Multiple calculation modes: percentage of, percentage change, and more
- Real-time results as you type
- Clean, simple interface — no ads cluttering the page
- Works on desktop and mobile
- Free with no account required
Quick Percentage Tips
A handy mental math trick: X% of Y is always the same as Y% of X. So 8% of 50 equals 50% of 8, which is 4 — much easier to calculate in your head. For percentage change, remember the formula: ((new value - old value) / old value) x 100. A positive result means an increase; a negative result means a decrease.
Frequently Asked Questions
How do I calculate percentage increase?
Subtract the original value from the new value, divide the result by the original value, and multiply by 100. For example, going from 200 to 250 is a ((250-200)/200) x 100 = 25% increase.
What is the difference between percentage and percentage points?
Percentage points measure the arithmetic difference between two percentages. If a rate increases from 5% to 8%, that is a 3 percentage point increase — but a 60% increase in relative terms. The distinction matters in finance, economics, and statistics.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 is what percent of 120? (30 / 120) x 100 = 25%.