Percentage Calculator

Free Online Percentage Calculator – Calculate Percentages Instantly

Introduction

Need to calculate percentages quickly and accurately? Our Percentage Calculator handles all types of percentage calculations: find what percentage one number is of another, calculate percentage of a number, or determine percentage increase/decrease. Perfect for students, business professionals, shoppers, and anyone working with percentages.

This free tool is essential for everyday math, financial calculations, grade calculations, discounts, tips, and more. No complex formulas to remember – just enter your numbers and get instant results.

What is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. The word "percent" literally means "per hundred." Percentages make it easy to compare proportions and understand relative values.

Three Types of Percentage Calculations

Our calculator handles all common percentage scenarios:

1. Percentage of a Number (What is X% of Y?)

Calculate what a certain percentage of a number equals.

• Example: What is 20% of 500?
• Formula: (20 / 100) × 500 = 100
• Use Cases: Sales discounts, tax calculations, tips

2. Find the Percentage (X is what % of Y?)

Determine what percentage one number represents of another.

• Example: 75 is what % of 300?
• Formula: (75 / 300) × 100 = 25%
• Use Cases: Grade calculations, completion rates, market share

3. Percentage Change (Increase/Decrease)

Calculate the percentage difference between two numbers.

• Example: From 100 to 150
• Formula: ((150 - 100) / 100) × 100 = +50%
• Use Cases: Price changes, growth rates, stock performance

Common Real-World Uses

Percentages appear everywhere in daily life:

Shopping and Discounts

• Sale Prices: "30% off" – calculate final price
• Sales Tax: Add 7% tax to purchase price
• Coupons: "Save 15%" – find savings amount
• Price Comparisons: Which deal saves more?

Restaurants and Tipping

• Standard Tip: Calculate 15%, 18%, or 20% tip
• Split Bills: Divide total with tip included
• Service Charges: Understand automatic gratuity

Finance and Business

• Interest Rates: Calculate loan interest or savings growth
• Profit Margins: Determine markup percentages
• Commission: Calculate sales commissions
• Investment Returns: Track portfolio performance
• Budget Allocation: Distribute expenses by percentage

Education and Grades

• Test Scores: Convert points to percentage grades
• GPA Calculation: Understand grade percentages
• Attendance: Track attendance percentage
• Improvement: Calculate grade improvement

Industry-Specific Applications

Different fields rely heavily on percentage calculations:

Retail and E-commerce

Retailers use percentages for:

• Pricing strategies and markups
• Discount campaigns and promotions
• Inventory turnover rates
• Conversion rate optimization
• Customer retention rates

Healthcare and Fitness

Health professionals use percentages to:

• Calculate body fat percentage
• Track weight loss/gain progress
• Measure medication dosages
• Analyze success rates of treatments
• Monitor vital sign changes

Marketing and Analytics

Marketers track percentages for:

• Conversion Rates: Visitors who become customers
• Click-Through Rates: Ad engagement metrics
• Bounce Rates: Website visitor behavior
• ROI: Return on investment calculations
• Market Share: Company's portion of total market

Real Estate

Real estate professionals calculate:

• Down payment percentages (typically 20%)
• Commission rates (usually 5-6%)
• Property value appreciation
• Mortgage interest rates
• Rental yield percentages

How to Use the Calculator

Our tool makes percentage calculations effortless:

For "What is X% of Y?"

Step 1: Enter the percentage (e.g., 15)
Step 2: Enter the total number (e.g., 200)
Step 3: Click Calculate
Result: 30 (15% of 200 is 30)

For "X is what % of Y?"

Step 1: Enter the part (e.g., 45)
Step 2: Enter the whole (e.g., 180)
Step 3: Click Calculate
Result: 25% (45 is 25% of 180)

For Percentage Change

Step 1: Enter the original value (e.g., 100)
Step 2: Enter the new value (e.g., 125)
Step 3: Click Calculate
Result: +25% (increased by 25%)

Percentage Formulas Explained

Understanding the math behind percentages:

Basic Percentage Formula

Percentage = (Part / Whole) × 100

Example: What percentage is 30 out of 150?
(30 / 150) × 100 = 20%

Finding a Percentage of a Number

Result = (Percentage / 100) × Number

Example: What is 35% of 200?
(35 / 100) × 200 = 70

Percentage Increase Formula

% Increase = ((New - Old) / Old) × 100

Example: From 50 to 75
((75 - 50) / 50) × 100 = +50%

Percentage Decrease Formula

% Decrease = ((Old - New) / Old) × 100

Example: From 100 to 80
((100 - 80) / 100) × 100 = -20%

Common Percentage Calculations

Quick reference for everyday scenarios:

Standard Tips

• 15% tip: Multiply bill by 0.15
• 18% tip: Multiply bill by 0.18
• 20% tip: Divide bill by 5

Common Discounts

• 10% off: Multiply price by 0.90
• 25% off: Multiply price by 0.75
• 50% off: Divide price by 2

Sales Tax

• 5% tax: Multiply by 1.05
• 7% tax: Multiply by 1.07
• 10% tax: Multiply by 1.10

Avoiding Common Mistakes

Don't make these percentage errors:

Mistake 1: Confusing Percentage Points with Percentages

Wrong: "Interest increased from 5% to 10%, a 5% increase"
Right: "That's a 5 percentage point increase, or a 100% increase"

Mistake 2: Adding Percentages Incorrectly

Wrong: 20% discount + 10% discount = 30% total discount
Right: Apply sequentially: First 20% off, then 10% off remaining = 28% total

Mistake 3: Percentage of Different Bases

Wrong: Comparing 50% of 100 with 50% of 200 as equal
Right: 50% of 100 = 50, but 50% of 200 = 100 (different amounts)

Mistake 4: Reversing Increase/Decrease

Wrong: If price increases 50% then decreases 50%, you're back to original
Right: $100 + 50% = $150, then $150 - 50% = $75 (not $100!)

Advanced Percentage Concepts

Beyond basic calculations:

Compound Percentages

When percentages are applied repeatedly (like compound interest), the effect multiplies rather than adds.

Percentage Points

The absolute difference between two percentages. If unemployment goes from 5% to 7%, that's a 2 percentage point increase (but a 40% relative increase).

Basis Points

One basis point = 0.01%. Used in finance for interest rates and investment returns. 100 basis points = 1%.

Tips for Mental Math

Calculate percentages quickly in your head:

10% Shortcut

Move decimal point one place left. 10% of 250 = 25.0

5% Shortcut

Find 10%, then divide by 2. 5% of 80 = (8 ÷ 2) = 4

1% Shortcut

Move decimal point two places left. 1% of 350 = 3.50

25% Shortcut

Divide by 4. 25% of 200 = 200 ÷ 4 = 50

50% Shortcut

Divide by 2. 50% of any number is half.

Privacy and Security

Your calculations are completely private:

• No Data Storage: We never save your numbers
• Client-Side Processing: All calculations happen in your browser
• No Account Required: Use anonymously
• Secure Connection: All data transmission is encrypted

Mobile and Cross-Device Usage

Our calculator works perfectly everywhere:

• Responsive design for smartphones and tablets
• Touch-optimized number inputs
• Works offline once loaded
• No app installation needed
• Perfect for shopping, dining, or on-the-go calculations

Conclusion

Percentages are fundamental to modern life, appearing in shopping, finance, education, business, and countless other areas. Our free percentage calculator makes these essential calculations instant and error-free, whether you're calculating discounts, tips, grades, growth rates, or any other percentage-based value.

With three powerful calculation modes and instant results, you'll never struggle with percentage math again. Bookmark this page and use it whenever you need quick, accurate percentage calculations. From everyday shopping to complex financial analysis, our calculator has you covered!