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Percentage Calculator — Solve Any % Problem in Seconds
Percentage Calculator helps you solve all percentage problems instantly: What is X% of Y? X is what % of Y? % increase, % decrease, discounts, tips, grades, and more — with clear, step-by-step explanations.
20% of 150 = 30
(20 × 150) ÷ 100 = 3000 ÷ 100 = 30
Percentage Calculator: Why You Need It
Percentages are everywhere — discounts, taxes, grades, interest, growth rates — yet many struggle with the math. Our Percentage Calculator eliminates guesswork and gives you accurate results with full working — perfect for students, shoppers, and professionals.
Common Use Cases
- 🛍️ Shopping — calculate final price after 30% discount
- 🍽️ Tips — 15% or 20% of your restaurant bill
- 🎓 Grades — what score do you need to get an A?
- 📈 Business — profit margin, growth rate, tax amount
- 📊 Data Analysis — proportion of responses, survey results
Key Percentage Formulas
| Scenario | Formula | Example |
|---|---|---|
| What is X% of Y? | (X × Y) ÷ 100 | 25% of 200 = (25 × 200) ÷ 100 = 50 |
| X is what % of Y? | (X ÷ Y) × 100 | 45 is what % of 180? → (45 ÷ 180) × 100 = 25% |
| % Increase | ((New – Original) ÷ Original) × 100 | From 80 to 100 → ((100–80)/80)×100 = 25% |
| % Decrease | ((Original – New) ÷ Original) × 100 | From 120 to 90 → ((120–90)/120)×100 = 25% |
Source: Khan Academy – Ratios & Percentages
How to Calculate Percentages Manually
Understanding the logic helps you verify results from any Percentage Calculator:
- Convert % to decimal: Divide by 100 (e.g., 18% → 0.18)
- Multiply: Decimal × Base number (e.g., 0.18 × 250 = 45)
- For “X is what % of Y?”: Divide first (X/Y), then ×100
💡 Pro Tip: To find 10% of any number, just move the decimal point one place left (e.g., 10% of 450 = 45).
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Frequently Asked Questions
Q: Can I calculate compound percentage (e.g., successive discounts)?
A: Not directly in this tool — but you can chain calculations. Example: 20% off, then 10% off:
Step 1: 100 – 20% = 80
Step 2: 80 – 10% = 72
Total discount = 28% (not 30%!).
Q: Does it support negative numbers?
A: Yes! For % change (e.g., profit/loss), negative values work correctly.
Q: Is there a mobile app?
A: No app needed — our Percentage Calculator works perfectly on iPhone, Android, and tablets — no installation required.
