How to Use the Percentage Calculator
This calculator has four modes — each solving a different type of percentage problem. Select the mode that matches your question:
- What is X% of Y? — Enter the percentage and the number. Use this for discounts, tips, GST amounts, and exam marks calculation.
- What % is X of Y? — Enter two numbers to find what percentage one is of the other. Use this for finding your percentage marks, profit margins, and ratios.
- % Increase / Decrease — Enter an original and new value to find the percentage change. Use this for salary hikes, price changes, and growth rates.
- Find Original Number — Enter a final value and the percentage that was applied to find the original number. Use this for finding pre-GST price or pre-discount price.
💡 Tip: Use the "Find Original Number" mode to calculate the pre-GST price of any product. Enter the MRP and select the GST rate (5%, 12%, 18%, or 28%) to find the original price before tax.
Percentage Formulas — Complete Reference
Here are all the percentage formulas you need, with examples:
(15 ÷ 100) × 800 = ₹120
(45 ÷ 200) × 100 = 22.5%
((650-500) ÷ 500) × 100 = 30% increase
((800-600) ÷ 800) × 100 = 25% decrease
₹1180 ÷ 1.18 = ₹1000
₹400 ÷ 0.80 = ₹500
Common Percentage Calculations in Daily Life
Calculating GST in India
GST (Goods and Services Tax) is applied at rates of 5%, 12%, 18%, or 28% depending on the product category. Here is how to calculate GST:
- GST amount: Original price × GST rate ÷ 100
- Total price with GST: Original price × (1 + GST rate/100)
- Original price from MRP: MRP ÷ (1 + GST rate/100)
| GST Rate | Common Products | ₹1000 base → Total with GST |
|---|---|---|
| 5% | Essential foods, books, transport | ₹1,050 |
| 12% | Processed foods, mobiles, computers | ₹1,120 |
| 18% | Electronics, restaurants, software | ₹1,180 |
| 28% | Luxury goods, cars, tobacco | ₹1,280 |
Calculating exam percentage marks
To find your percentage in an exam: divide marks obtained by total marks and multiply by 100.
Example: Scored 450 out of 600 → (450 ÷ 600) × 100 = 75%
| Grade | Percentage Range | CBSE Classification |
|---|---|---|
| A1 | 91–100% | Outstanding |
| A2 | 81–90% | Excellent |
| B1 | 71–80% | Very Good |
| B2 | 61–70% | Good |
| C1 | 51–60% | Above Average |
| C2 | 41–50% | Average |
| D | 33–40% | Pass |
Calculating discounts while shopping
To find the discounted price: multiply the original price by (1 - discount%/100).
Example: ₹2,000 shirt at 30% discount → ₹2,000 × (1 - 30/100) = ₹2,000 × 0.70 = ₹1,400
Calculating salary hike percentage
To find your salary hike percentage: ((New Salary - Old Salary) ÷ Old Salary) × 100.
Example: Salary increased from ₹40,000 to ₹46,000 → ((46,000 - 40,000) ÷ 40,000) × 100 = 15% hike
Quick Percentage Reference Table
| Percentage | Fraction | Decimal | Of ₹1,000 |
|---|---|---|---|
| 1% | 1/100 | 0.01 | ₹10 |
| 5% | 1/20 | 0.05 | ₹50 |
| 10% | 1/10 | 0.10 | ₹100 |
| 12.5% | 1/8 | 0.125 | ₹125 |
| 20% | 1/5 | 0.20 | ₹200 |
| 25% | 1/4 | 0.25 | ₹250 |
| 33.33% | 1/3 | 0.333 | ₹333 |
| 50% | 1/2 | 0.50 | ₹500 |
| 75% | 3/4 | 0.75 | ₹750 |