Percentage Calculator
This percentage calculator solves three common problems: finding what percent of a number is, calculating what percentage one number is of another, and computing percentage change between two values. Enter your numbers and get instant results with step-by-step explanations.
Percentage Calculator
Choose a calculation mode below to solve common percentage problems instantly.
Calculate what a specific percentage of a number is. For example, what is 15% of 200?
Frequently Asked Questions
How do you calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 25% of 200 is (200 x 25) / 100 = 50. You can also convert the percentage to a decimal first by dividing by 100 (25% becomes 0.25), then multiply: 200 x 0.25 = 50. This method works for any percentage and any number, including decimals and values greater than 100%.
What is the percentage change formula?
Percentage change = ((New Value - Old Value) / Old Value) x 100. A positive result indicates an increase, while a negative result indicates a decrease. For example, if a price goes from $80 to $100, the percentage change is ((100 - 80) / 80) x 100 = 25% increase. This formula is widely used in finance, economics, and data analysis to measure relative changes over time.
How do you find what percentage one number is of another?
Divide the part by the whole and multiply by 100. The formula is: Percentage = (Part / Whole) x 100. For example, if you scored 45 out of 60 on a test, the percentage is (45 / 60) x 100 = 75%. This calculation is useful for grades, statistics, discounts, and any situation where you need to express a ratio as a percentage.
How do you calculate percentage increase?
Percentage increase = ((New Value - Original Value) / Original Value) x 100. The result is always positive for a true increase. For example, if your salary went from $50,000 to $55,000, the increase is ((55,000 - 50,000) / 50,000) x 100 = 10%. To find the new value after a known percentage increase, multiply the original by (1 + percentage/100).
How do you calculate percentage decrease?
Percentage decrease = ((Original Value - New Value) / Original Value) x 100. For example, if a product price drops from $120 to $90, the decrease is ((120 - 90) / 120) x 100 = 25%. Note that a 25% decrease from $120 gives $90, but a 25% increase from $90 gives $112.50, not $120. Percentage decreases and increases are not symmetrical.
What is the difference between percentage and percentile?
A percentage represents a portion out of 100, while a percentile indicates a ranking position within a data set. For example, scoring 85% on a test means you answered 85 out of 100 questions correctly. Being in the 85th percentile means you scored higher than 85% of all test-takers. Percentages measure absolute performance; percentiles measure relative standing compared to others.
How do you convert a fraction to a percentage?
Divide the numerator by the denominator and multiply by 100. For example, 3/8 as a percentage is (3 / 8) x 100 = 37.5%. For simple fractions, you can find an equivalent fraction with 100 as the denominator: 1/4 = 25/100 = 25%. Common conversions worth memorizing include 1/2 = 50%, 1/3 = 33.33%, 1/4 = 25%, 1/5 = 20%, and 3/4 = 75%.
How to Calculate Percentages
What is a Percentage Calculator?
A percentage calculator is a tool that helps you quickly solve common percentage problems. Percentages represent a fraction of 100 and are used in everyday life for discounts, taxes, tips, grades, statistics, and financial calculations. This calculator supports three types of percentage operations: finding a percentage of a number, determining what percentage one number is of another, and calculating the original value before a percentage increase or decrease.
Percentage Formulas
1. What is X% of Y?
Multiply the percentage (as a decimal) by the number:
2. X is what % of Y?
Divide the part by the whole and multiply by 100:
3. X is Y% more/less than what?
Reverse a percentage increase or decrease to find the original value:
For "more": Original = X / (1 + Y/100)
For "less": Original = X / (1 - Y/100)
Remember: "percent" literally means "per hundred." So 25% is the same as 25/100 or 0.25 as a decimal.
Examples
Example 1: Finding a Percentage of a Number
What is 15% of 200?
(15 / 100) × 200 = 30
Example 2: Finding What Percentage One Number Is of Another
45 is what % of 180?
(45 / 180) × 100 = 25%
Example 3: Reversing a Percentage Increase
120 is 20% more than what?
120 / (1 + 20/100) = 120 / 1.20 = 100
Example 4: Reversing a Percentage Decrease
80 is 20% less than what?
80 / (1 - 20/100) = 80 / 0.80 = 100
Common Use Cases
- Shopping discounts: Calculate how much you save with a 30% off coupon on a $85 item.
- Tax calculations: Determine the tax amount on a purchase given a sales tax percentage.
- Tip calculations: Quickly figure out a 18% or 20% tip at a restaurant.
- Grade calculations: Find what percentage score you achieved on an exam (e.g., 42 out of 50).
- Financial analysis: Calculate profit margins, returns on investment, and markup percentages.
- Data analysis: Determine what proportion of a dataset meets certain criteria.
- Price reversal: Find the original price before a sale discount or tax was applied.
Tips
- To convert a percentage to a decimal, divide by 100 (e.g., 25% = 0.25).
- To convert a decimal to a percentage, multiply by 100 (e.g., 0.75 = 75%).
- Percentage increase and decrease are not symmetric: a 50% increase followed by a 50% decrease does not return to the original value.
- When calculating "% more/less than," be careful not to confuse "percentage points" with "percent change."
- For quick mental math, remember that X% of Y equals Y% of X (e.g., 8% of 50 = 50% of 8 = 4).