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." The symbol % denotes percentage.
Percentages are used everywhere — from bank interest rates and exam scores to discounts, tax calculations, and business growth metrics. Being comfortable with percentage calculations is a fundamental life skill.
Basic Percentage Formulas
1. What is X% of Y?
Formula: Result = (X / 100) × Y
Example: What is 20% of ₹5,000? = (20 / 100) × 5,000 = ₹1,000
Use case: Calculating discount amounts, commission, tips, tax
2. X is what percent of Y?
Formula: Percentage = (X / Y) × 100
Example: 750 is what percent of 3,000? = (750 / 3,000) × 100 = 25%
Use case: Calculating exam scores, market share, completion percentage
3. Percentage Change (Increase or Decrease)
Formula: % Change = [(New Value − Old Value) / Old Value] × 100
Example: A stock went from ₹200 to ₹250. What is the percentage increase? = [(250 − 200) / 200] × 100 = 25% increase
Use case: Business growth, salary hikes, price changes, inflation
4. Finding the Original Value from a Percentage
Formula: Original = (Value / Percentage) × 100
Example: After a 20% discount, the price is ₹800. What was the original price? = (800 / 80) × 100 = ₹1,000
Use case: Reverse-calculating original prices, finding base salary from percentage hike
Percentage Calculations in Everyday Life
Shopping Discounts
When a product shows "30% off", you can calculate:
- Original Price: ₹2,000
- Discount: 30% of ₹2,000 = ₹600
- Final Price: ₹2,000 − ₹600 = ₹1,400
Bank Interest
Simple interest uses percentage:
- Principal: ₹1,00,000
- Rate: 6% per annum
- Interest for 1 year: 6% of ₹1,00,000 = ₹6,000
Exam Scores
- Marks obtained: 450 out of 600
- Percentage: (450 / 600) × 100 = 75%
Salary Hike
- Current salary: ₹50,000
- Hike: 15%
- Increment: 15% of ₹50,000 = ₹7,500
- New salary: ₹57,500
GST Calculation
- Product price (exclusive of GST): ₹10,000
- GST: 18%
- GST amount: 18% of ₹10,000 = ₹1,800
- Total: ₹11,800
Percentage vs Percentage Points – Common Confusion
Many people confuse "percentage" with "percentage points":
- If interest rates go from 4% to 6%, that's an increase of 2 percentage points
- But it's a 50% increase in the interest rate itself (2/4 × 100 = 50%)
This distinction matters in finance, economics, and political reporting.
Percentages in Finance
Compound Annual Growth Rate (CAGR)
CAGR shows the annual growth rate of an investment over multiple years:
Formula: CAGR = [(Final Value / Initial Value)^(1/Years)] − 1 × 100
Example: Investment grew from ₹1,00,000 to ₹1,61,051 in 5 years: CAGR = (1,61,051 / 1,00,000)^(1/5) − 1 = 10% per annum
Inflation Rate
If a product cost ₹100 last year and ₹106 this year: Inflation = (6/100) × 100 = 6%
Loan Interest (EMI)
EMI calculations involve monthly percentage rates. See our EMI Calculator for detailed loan calculations.
How to Use Our Percentage Calculator
- Select the type of calculation – "X% of Y", "X is what % of Y", or "% change"
- Enter your values – Fill in the required numbers
- View the result instantly
👉 Try the Percentage Calculator
Common Percentage Tricks for Mental Maths
- 10% of any number = Move the decimal one place left (10% of 350 = 35)
- 5% of any number = Half of 10% (5% of 350 = 17.5)
- 1% of any number = Move decimal two places left (1% of 350 = 3.5)
- 25% of any number = Divide by 4 (25% of 200 = 50)
- 50% of any number = Divide by 2 (50% of 480 = 240)
Frequently Asked Questions
Q: How do I calculate percentage increase? A: % Increase = [(New Value − Old Value) / Old Value] × 100. If salary increased from ₹40,000 to ₹46,000: [(46,000 − 40,000) / 40,000] × 100 = 15% increase.
Q: What is the difference between percent and percentage? A: "Percent" is used with a specific number (e.g., "15 percent"), while "percentage" refers to a general proportion without a specific number (e.g., "a small percentage").
Q: How do I calculate percentage marks in exams? A: Percentage = (Marks Obtained / Total Marks) × 100. If you scored 420 out of 500: (420 / 500) × 100 = 84%.
Q: What is a good percentage score? A: In Indian education, 60%+ is typically considered First Class, 75%+ is Distinction, and 90%+ is considered excellent. Requirements vary by institution and purpose.
Q: How is percentage used in GST calculation? A: GST is a percentage of the transaction value. 18% GST on ₹10,000 means you pay ₹1,800 as tax. Use our GST Calculator for instant GST calculations.
Disclaimer
This percentage calculator is for educational and informational purposes only. Always verify critical financial calculations with a qualified professional.