ganak.appReverse Percentage Calculator
Find original value before discounts or taxes.
Original Price Before Discount
If you paid ₹750 after a 25% discount, the original price was ₹1,000.
Pre-Tax Amount
If the final price including 18% GST is ₹1,180, the pre-tax amount is ₹1,000.
Markup & Margin
If you sell a product for ₹150 that cost ₹100, your profit is ₹50, margin is 33.33%, and markup is 50%.
A percentage is a way to express a number as a fraction of 100. The word "percent" comes from the Latin "per centum," meaning "out of one hundred." When you see 25%, it simply means 25 out of 100, or one-quarter of the whole. Percentages make it easy to compare proportions and understand relative sizes without dealing with complex fractions. Percentages are everywhere in daily life: discounts at stores, interest rates on loans, tax calculations, exam scores, and statistical data. Understanding how to work with percentages helps you make better financial decisions, interpret data correctly, and solve practical problems quickly.
Finding X% of a number: Multiply the number by X and divide by 100. For example, 15% of 200 is (15 ÷ 100) × 200 = 30. This is useful for calculating discounts, tips, or any portion of a whole.
Finding what percent X is of Y: Divide X by Y and multiply by 100. For example, if you scored 45 out of 60, your percentage is (45 ÷ 60) × 100 = 75%. This helps you understand your performance or compare two quantities.
Finding the whole when you know the part and percentage: Multiply the part by 100 and divide by the percentage. For example, if 30 is 15% of a number, that number is (30 × 100) ÷ 15 = 200. This is helpful for reverse calculations like finding original prices before discounts.
Percentage change: Calculate the change (final - initial), divide by the initial value, and multiply by 100. For example, if a price goes from ₹100 to ₹120, the percentage change is ((120 - 100) ÷ 100) × 100 = 20% increase.
These two concepts are often confused, but they serve different purposes. Percentage change measures how much a value has moved from a specific starting point. It always has a direction (increase or decrease) and depends on which value you consider as the initial one. Use percentage change when tracking growth over time, like salary increases, stock price movements, or sales growth.
Percentage difference, on the other hand, compares two values relative to their average. It treats both values equally and doesn't depend on which one you call "first" or "second." The formula is: |V1 - V2| ÷ ((V1 + V2) ÷ 2) × 100. Use percentage difference when comparing two independent measurements, like test scores from two students or prices from two different stores.
- Shopping discounts: A ₹2,000 shirt with a 30% discount costs ₹2,000 - (30% of ₹2,000) = ₹2,000 - ₹600 = ₹1,400.
- Exam performance: Scoring 45 out of 60 marks means (45 ÷ 60) × 100 = 75% performance.
- Salary hike: A 15% raise on ₹50,000 monthly salary means an increase of ₹7,500, bringing the new salary to ₹57,500.
- Investment returns: If your ₹10,000 investment grows to ₹12,000, that's a ((12,000 - 10,000) ÷ 10,000) × 100 = 20% return.
- Tax calculations: If GST is 18% on a ₹1,000 purchase, the tax amount is ₹180, making the total ₹1,180.
- Reverse percentage: If you paid ₹750 after a 25% discount, the original price was ₹750 ÷ 0.75 = ₹1,000.