Free Online Percentage Calculator
Looking for a fast and reliable way to calculate percentage values? Our free percentage calculator online tool helps you solve any percentage problem in seconds. Whether you need to find what percent one number is of another, calculate a percentage increase or decrease, or reverse-engineer an original price before a discount, this percent calculator has you covered.
Percentages are everywhere in daily life—from shopping discounts and restaurant tips to exam grades and financial reports. Understanding how to calculate percentage easily is an essential skill, and our calculator makes it effortless. Simply enter your numbers, and the results appear instantly as you type. No buttons to click, no page reloads, no waiting.
Why Use Our Free Online Percentage Calculator?
Instant Results
Results appear as you type—no buttons to click, no waiting for page reloads.
Six Calculators in One
Handle any percentage problem with our comprehensive suite of calculation tools.
Works on Any Device
Fully responsive design works perfectly on phones, tablets, and desktop computers.
100% Private
All calculations happen in your browser. We never see or store your numbers.
Completely Free
No registration, no fees, no limits. Use as often as you need.
Easy Copy & Share
One-click copy button lets you quickly use results in other applications.
What is a Percentage?
A percentage is a way of expressing a number as a fraction of 100. The word "percent" comes from the Latin "per centum," meaning "by the hundred." When you see 25%, it means 25 out of every 100, or simply 25/100, which equals 0.25 as a decimal.
Percentages make it easy to compare different quantities on a common scale. For example, saying "you saved 20%" is more intuitive than saying "you saved one-fifth of the original price." This is why percentages are used extensively in:
- Shopping and retail: Discounts, sales tax, markups
- Finance: Interest rates, investment returns, loan APRs
- Education: Test scores, grade calculations, class rankings
- Business: Profit margins, growth rates, market share
- Health: Body fat percentage, medication dosages, nutritional values
- Statistics: Survey results, probability, data analysis
How to Calculate Percentage: The Basic Formula
The fundamental percentage formula is straightforward:
Percentage = (Part ÷ Whole) × 100
For example, if you scored 45 out of 60 on a test and want to know your percentage score:
- Part = 45 (your score)
- Whole = 60 (total possible points)
- Percentage = (45 ÷ 60) × 100 = 75%
Our percentage calculator automates this process. Just enter the part and whole values, and the result appears immediately. You can also work backwards—if you know the percentage and the whole, you can find the part.
Types of Percentage Calculations
Our free percentage calculator handles six different types of percentage problems. Here's a detailed explanation of each:
1. What is X% of Y? (Basic Percentage)
This is the most common percentage calculation. You want to find a specific percentage of a given number.
Formula: Result = (Percentage ÷ 100) × Number
Example: What is 15% of 200?
- Calculation: (15 ÷ 100) × 200 = 0.15 × 200 = 30
Real-world uses: Calculating tips at restaurants, finding discount amounts, determining tax on purchases, computing commission on sales.
2. X is What Percent of Y?
Use this when you have two numbers and want to know what percentage the first is of the second.
Formula: Percentage = (Part ÷ Whole) × 100
Example: 45 is what percent of 180?
- Calculation: (45 ÷ 180) × 100 = 0.25 × 100 = 25%
Real-world uses: Calculating test scores, determining what portion of your budget you spent, finding batting averages, analyzing survey results.
3. Percentage Change (Increase or Decrease)
The percentage increase calculator and percentage decrease calculator help you determine how much a value has changed relative to its original amount.
Formula: Percentage Change = ((New Value − Old Value) ÷ |Old Value|) × 100
Example: A stock price went from $80 to $100. What's the percentage change?
- Calculation: ((100 − 80) ÷ 80) × 100 = (20 ÷ 80) × 100 = +25%
Real-world uses: Tracking investment performance, measuring sales growth, comparing prices over time, analyzing weight loss/gain progress.
4. Percentage Difference Between Two Values
Unlike percentage change (which measures change from a starting point), percentage difference measures how different two values are relative to their average. This is useful when neither value is the "original."
Formula: Percentage Difference = (|Value1 − Value2| ÷ ((Value1 + Value2) ÷ 2)) × 100
Example: Compare prices of $40 and $60
- Average: (40 + 60) ÷ 2 = 50
- Difference: |40 − 60| = 20
- Percentage Difference: (20 ÷ 50) × 100 = 40%
Real-world uses: Comparing competing product prices, analyzing experimental results, benchmarking performance metrics.
5. Add or Subtract a Percentage
Quickly increase or decrease a number by a given percentage. This is essentially a two-step calculation combined into one.
Formulas:
- Add: Result = Number + (Number × Percentage ÷ 100) = Number × (1 + Percentage/100)
- Subtract: Result = Number − (Number × Percentage ÷ 100) = Number × (1 − Percentage/100)
Example: Add 20% to $150
- Calculation: 150 + (150 × 0.20) = 150 + 30 = $180
Real-world uses: Adding sales tax to prices, calculating tips, applying markups, figuring discounted prices.
6. Reverse Percentage (Find Original Value)
When you know the final amount after a percentage was added, this calculator finds the original value before the percentage was applied. This is often called "working backwards" from a percentage.
Formula: Original Value = Final Value ÷ (1 + Percentage ÷ 100)
Example: A shirt costs $115 after 15% tax. What was the pre-tax price?
- Calculation: 115 ÷ (1 + 0.15) = 115 ÷ 1.15 = $100
Real-world uses: Finding pre-tax prices, calculating original amounts before markups, reverse-engineering base salaries from total compensation.
Practical Examples: Using the Percentage Calculator in Real Life
Shopping and Discounts
Imagine you're shopping and see a jacket originally priced at $120 with a 30% discount. How much will you save, and what's the final price?
- Savings: Use "What is X% of Y?" → 30% of $120 = $36 savings
- Final price: Use "Subtract percentage" → $120 − 30% = $84
Restaurant Tips
Your dinner bill is $85, and you want to leave an 18% tip. How much should you tip?
- Use "What is X% of Y?" → 18% of $85 = $15.30 tip
- Total with tip: $85 + $15.30 = $100.30
Grade Calculations
You scored 42 points out of 50 on an exam. What's your percentage grade?
- Use "X is what % of Y?" → 42 is what % of 50 = 84%
Investment Returns
Your investment grew from $5,000 to $6,250 over a year. What was your return?
- Use "Percentage Change" → From $5,000 to $6,250 = +25% return
Sales Tax Calculation
You bought electronics for $299 in a state with 8.25% sales tax. What's the total?
- Use "Add percentage" → $299 + 8.25% = $323.67 total
Tips for Accurate Percentage Calculations
Use Decimal Points Correctly
Our calculator accepts both periods (.) and commas (,) as decimal separators. Enter "3.5" or "3,5" for three and a half—both work perfectly.
Watch for Percentage vs. Decimal
Enter percentages as whole numbers, not decimals. For 25%, type "25" not "0.25". The calculator handles the conversion automatically.
Choose the Right Calculator
Make sure you're using the appropriate calculation type. "Percentage change" and "percentage difference" give different results—understand when to use each.
Double-Check Your Inputs
Results update instantly as you type. If something looks wrong, verify you entered the numbers in the correct fields—part vs. whole, from vs. to.
Quick Percentage Reference Table
Here are some commonly used percentage conversions for quick mental math:
| Percentage |
As a Decimal |
As a Fraction |
Quick Calculation Tip |
| 10% |
0.10 |
1/10 |
Move decimal one place left |
| 20% |
0.20 |
1/5 |
Divide by 5 |
| 25% |
0.25 |
1/4 |
Divide by 4 |
| 33.33% |
0.333... |
1/3 |
Divide by 3 |
| 50% |
0.50 |
1/2 |
Divide by 2 (halve it) |
| 75% |
0.75 |
3/4 |
Find 50% + 25% |
| 100% |
1.00 |
1/1 |
The whole amount |
Frequently Asked Questions About Percentages
To calculate percentage of a number, multiply the number by the percentage and divide by 100. For example, to find 15% of 80: multiply 80 × 15 = 1,200, then divide by 100 = 12. Our calculator does this instantly—just enter the values and see the result.
Percentage change measures how much a value increased or decreased from an original starting point (e.g., "sales increased by 20% from last year"). Percentage difference compares two values when neither is the "original"—it uses their average as the reference point (e.g., "Product A costs 40% more than the average of A and B"). Use percentage change for tracking progress over time; use percentage difference for comparing two independent values.
Use the reverse percentage calculator. If you know the sale price and the discount percentage, divide the sale price by (1 − discount/100). For example, if something costs $80 after a 20% discount: $80 ÷ (1 − 0.20) = $80 ÷ 0.80 = $100 original price. Our reverse percentage tool handles this calculation for you.
To calculate percentage increase, subtract the old value from the new value, divide by the old value, and multiply by 100. Formula: ((New − Old) ÷ Old) × 100. For example, if your salary went from $50,000 to $55,000: ((55,000 − 50,000) ÷ 50,000) × 100 = 10% increase. Use our percentage change calculator for instant results.
Yes! Percentages over 100% are common in many contexts. A 150% increase means the value more than doubled. If your investment grew from $100 to $300, that's a 200% increase. Our calculator handles percentages of any size, including values over 100%.
To calculate your grade percentage, divide your earned points by the total possible points and multiply by 100. Use our "X is what % of Y?" calculator—enter your score as the first number and the maximum possible score as the second. For example, 85 out of 100 points = 85%. If you have multiple assignments, add up all your earned points and all possible points before calculating.
Related Percentage Calculations You Might Need
Beyond basic percentage math, here are some specialized calculations our tool can help with:
- Tip Calculator: Use "What is X% of Y?" to calculate 15%, 18%, or 20% tips on restaurant bills.
- Discount Calculator: Use "Subtract percentage" to find sale prices, or "Reverse percentage" to find original prices.
- Tax Calculator: Use "Add percentage" to calculate total price including sales tax or VAT.
- Grade Calculator: Use "X is what % of Y?" to convert raw scores to percentage grades.
- Markup Calculator: Use "Add percentage" to calculate retail prices from wholesale costs.
- Profit Margin Calculator: Use "Percentage change" to determine profit margins between cost and selling price.
- Body Fat Percentage: Use "X is what % of Y?" if you know your fat mass and total body weight.
- Interest Rate Calculations: Use "Percentage change" to see how much interest added to your principal.
Start Calculating Percentages Now
Whether you're a student working on homework, a professional analyzing data, or a shopper comparing prices, our percentage calculator online tool is designed to make your life easier. Bookmark this page for quick access whenever you need to calculate percentage values accurately and efficiently.
Have a percentage problem? Scroll up and start calculating—it's free, instant, and works on any device. No downloads, no sign-ups, just fast and accurate percentage calculations whenever you need them.