Percentage Calculator
Calculate percentages, percentage change, increase, and decrease. Solve "X% of Y" and "X is what % of Y" problems instantly.
Our free Percentage Calculator solves every common percentage problem in seconds. Find what X% of a number is, determine what percentage one number is of another, or calculate the percentage increase or decrease between two… Use the fields above to enter values and get an instant answer. All processing happens on your device.
About This Calculator
Our free Percentage Calculator solves every common percentage problem in seconds. Find what X% of a number is, determine what percentage one number is of another, or calculate the percentage increase or decrease between two values. It covers the three question types people search for most: "What is 15% of 200?", "30 is what percent of 120?", and "What is the percentage change from 80 to 100?" Ideal for calculating discounts during shopping, figuring out tips at restaurants, grading exams, analyzing financial data, computing tax amounts, and any everyday situation that involves percentages.
How It Works
The calculator handles three modes. Mode 1 — "What is X% of Y?": multiplies Y by (X / 100). Mode 2 — "X is what percent of Y?": divides X by Y and multiplies by 100. Mode 3 — "Percentage change from X to Y": uses the formula [(Y - X) / X] x 100. A positive result means an increase; a negative result means a decrease. All calculations are performed instantly in your browser and results update in real time as you type.
Example Calculation
Example: What is 20% of 250? Answer: 50. If a price goes from $80 to $100, the percentage increase is [(100 - 80) / 80] x 100 = 25%. To find what percentage 15 is of 60: (15 / 60) x 100 = 25%.
How to Use
- Enter your values in the calculator fields above
- Click the calculate button or let the calculator auto-update
- Review your results instantly
- Adjust values as needed to see different scenarios
Frequently Asked Questions
How do I calculate X% of a number?
Multiply the number by the percentage divided by 100. For example, 20% of 350 = 350 x 0.20 = 70. This is useful for calculating tips (e.g., 18% of a $45 bill = $8.10), discounts, tax amounts, and commissions.
How do I calculate percentage increase or decrease?
Use the formula: [(New Value - Old Value) / Old Value] x 100. If your salary went from $50,000 to $55,000, the increase is [(55,000 - 50,000) / 50,000] x 100 = 10%. If a stock dropped from $120 to $96, the decrease is [(96 - 120) / 120] x 100 = -20%.
How do I calculate a sale or discount price?
Multiply the original price by the discount percentage as a decimal, then subtract. For example, a 30% discount on $80: discount amount = $80 x 0.30 = $24; sale price = $80 - $24 = $56. Or multiply by (1 - 0.30) = 0.70 directly: $80 x 0.70 = $56.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example, if you scored 42 out of 60 on a test: (42 / 60) x 100 = 70%. This works for grades, completion rates, market share, and any part-to-whole comparison.
What is the difference between percentage and percentage points?
A change from 10% to 15% is a 5 percentage-point increase but a 50% percentage increase (because 5 is 50% of 10). Percentage points measure the absolute difference between two percentages, while percentage change measures relative growth. Financial news often conflates the two, so this distinction matters.
Why Use Our Free Percentage Calculator Online?
Our Percentage Calculator uses standard formulas and works in your browser—no install or sign-up. Use it for homework, travel, or everyday conversions. Results are instant and we don't collect your inputs. Explore our other math and unit converters from the link below.