Percentage Calculator – 

Introduction to Percentages

Percentage Calculator are one of the most fundamental mathematical concepts used in everyday life, from calculating discounts during shopping to determining interest rates on loans. A Percentage Calculator simplifies these computations, making it easy for students, professionals, and businesses to perform accurate percentage-related calculations instantly.

What is a Percentage Calculator?

A Percentage Calculator is a digital tool that helps:
✔ Calculate percentage increase/decrease
✔ Determine percentage of a number
✔ Find original values before percentage changes
✔ Solve percentage-based word problems
✔ Convert between fractions, decimals, and percentages

Example Calculation:

• Problem: What is 25% of 200?

• Solution: 25% × 200 = 50

Basic Percentage Formulas

1. Percentage of a Number

Percentage = (Part/Whole) × 100

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

2. Find Part from Percentage

Part = (Percentage × Whole)/100

Example:
Find 15% of 300
(15 × 300)/100 = 45

3. Percentage Change

% Change = [(New Value – Old Value)/Old Value] × 100

Example:
Price increased from ₹50 to ₹65
[(65-50)/50] × 100 = 30% increase

4. Reverse Percentage (Find Original)

Original Value = (Final Value × 100)/(100 ± Percentage)

Example:
After 20% discount, price is ₹400
Original = (400×100)/(100-20) = ₹500

How to Use a Percentage Calculator

Step 1: Select Calculation Type

Choose between:

• X% of Y

• X is what % of Y

• Percentage increase/decrease

• Reverse percentage

Step 2: Enter Known Values

Input the numbers provided in your problem

Step 3: View Results

Get instant calculation with step-by-step solution

Practical Applications of Percentage Calculations

1. Shopping & Discounts

Calculate:

• Final price after discount

• Savings amount

• Multiple discounts stacking

Example:
₹2,000 shirt with 30% off + additional 10%
First discount: ₹600 (₹1,400 remaining)
Second discount: ₹140
Final price: ₹1,260
Total savings: ₹740 (37%)

2. Financial Calculations

• Loan interest rates

• Investment returns

• Bank deposit growth

• Inflation adjustments

3. Academic Grading

• Test scores as percentages

• Grade improvements

• Weighted averages

4. Business Metrics

• Profit/loss percentages

• Sales growth

• Market share changes

• Employee performance metrics

Advanced Percentage Concepts

1. Percentage Points vs Percent

• Percentage Points: Absolute difference (e.g., 5% to 7% = 2 percentage points)

• Percent Change: Relative difference (e.g., 5% to 7% = 40% increase)

2. Compound Percentage Changes

For successive changes:
Final Value = Initial × (1 ± p₁) × (1 ± p₂)…

Example:
₹100 with 10% increase then 5% decrease:
100 × 1.10 × 0.95 = ₹104.50

3. Weighted Averages

Weighted % = Σ(value × weight)/Σweights

Example:
Test 1 (30% weight): 80%
Test 2 (70% weight): 90%
Overall = (80×30 + 90×70)/100 = 87%

Common Percentage Calculation Mistakes

1. Confusing Percentage Increase/Decrease
   Mistaking denominator between old and new values

2. Incorrect Order of Operations
   Forgetting proper sequence in compound changes

3. Percentage vs Percentage Points
   Using terms interchangeably when they differ

4. Base Value Errors
   Calculating percentages from wrong base amount

5. Sign Errors
   Mixing up positive/negative changes

Percentage Conversion Table