Percentage Calculator | Free Online Percentage Tool

📖 How to Use This Percentage Calculator

Select calculation type - Choose from "% of a number", "What % of number", or "% Increase/Decrease".

Enter your values - Input the numbers in the fields provided.

Get instant results - The calculator shows the answer with step-by-step formula explanation.

📊 Understanding Percentages

A percentage is a ratio expressed as a fraction of 100. The word "percent" means "per hundred" or "out of 100." Percentages are used everywhere in daily life: discounts at stores, tax rates, interest rates, test scores, and statistical data.

🧮 Percentage Formulas

1. Percentage of a number:
Result = (Percentage ÷ 100) × Number
Example: 20% of 200 = (20 ÷ 100) × 200 = 40

2. What percent of a number:
Percentage = (Part ÷ Whole) × 100
Example: 30 is what % of 200? (30 ÷ 200) × 100 = 15%

3. Percentage increase/decrease:
% Change = ((New - Original) ÷ Original) × 100
Example: 200 to 250 = +25% increase

💡 Common Percentage Applications

Discounts & Sales: Calculate how much you save (e.g., 20% off $50 = $10 saved)
Tips & Gratuity: Calculate restaurant tips (e.g., 15% of $80 = $12 tip)
Tax Calculations: Sales tax, VAT, GST (e.g., 8% sales tax on $100 = $8)
Grade & Test Scores: 45 correct out of 50 = 90% score
Investment Returns: $1,000 to $1,200 = 20% return
Population Growth: City population from 10,000 to 11,500 = 15% increase

💡 Tips for Working with Percentages

Convert to decimal first: 25% = 0.25, 8% = 0.08, 150% = 1.5
Use the "of" method: "of" means multiply (20% of 80 = 0.2 × 80 = 16)
For discounts: Final price = Original × (100% - Discount%) ÷ 100
For tax/tip add-on: Total = Original × (100% + Tax%) ÷ 100

❓ Frequently Asked Questions (FAQ)

How do I calculate 20% of 80?

Multiply 80 by 0.20 (since 20% = 0.20). 80 × 0.20 = 16. Our "% of a number" calculator does this instantly.

How do I calculate percentage increase?

Subtract the original from the new value, divide by the original, then multiply by 100. Example: 50 to 70 → (70-50)/50 = 0.4 → 40% increase.

How do I calculate percentage decrease?

Use the same formula: ((Original - New) ÷ Original) × 100. Example: 80 to 60 → (80-60)/80 = 0.25 → 25% decrease.

What is 10% of 50?

10% of 50 = 5. Because 50 × 0.10 = 5.

What is the percentage of 25 out of 200?

(25 ÷ 200) × 100 = 12.5%.

How accurate is this calculator?

Our calculator provides results with up to 4 decimal places for high precision. All calculations follow standard mathematical formulas.