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🧮 Math & Numbers · Free Tool

Free Percentage Calculator

Calculate percentages instantly — find % of any number, calculate percentage increase or decrease, reverse percentage, and much more. No signup, no ads blocking results.

% What is X% of Y?

Example: What is 20% of 500?

Result

% X is what % of Y?

Example: 45 is what % of 180?

Result

📈 Percentage Increase / Decrease

Find % change between two values

Percentage Change

🔁 Reverse Percentage

Find original value before % change

Original Value

➕ Add or Remove a Percentage

Add or subtract a % from any number

Result

📋 Marks / Score Percentage

Calculate percentage from marks obtained

Your Percentage

How to Calculate Percentage – Complete Guide with Formulas

percentage calculator percent formula percentage increase percentage decrease marks percentage reverse percentage

Percentage is one of the most used mathematical concepts in daily life. Whether you're calculating discounts at a shop, checking your exam marks, finding profit or loss in business, or analyzing data at work — percentage calculations come up constantly. Our free percentage calculator handles all of these calculations instantly so you don't need to do mental math or remember formulas.

What is Percentage?

The word "percent" comes from the Latin "per centum" meaning "per hundred." A percentage is simply a way to express a number as a fraction of 100. So when we say 25%, it means 25 out of every 100 parts. Percentages make it easy to compare different quantities on a common scale.

In mathematics, a percentage is denoted by the symbol %. For example, 45% means 45/100 = 0.45 in decimal form.

Basic Percentage Formula

Percentage = (Part ÷ Whole) × 100

This simple formula is the foundation of all percentage calculations. If you know any two of the three values (percentage, part, or whole), you can always find the third one.

How to Find X% of a Number

This is the most common percentage calculation. To find what X percent of Y is:

Result = (X ÷ 100) × Y

Example: What is 30% of 500? → (30 ÷ 100) × 500 = 0.30 × 500 = 150

This type of calculation is extremely useful for calculating discounts. If a product costs Rs. 2,000 and there is a 20% discount, you save Rs. 400 (20% of 2,000) and pay Rs. 1,600.

How to Calculate Percentage Increase

Percentage increase tells you how much something has grown relative to its original value. This is used in business for profit calculation, in finance for investment returns, and in studies for comparing test scores.

% Increase = ((New Value – Old Value) ÷ Old Value) × 100

Example: If your salary was Rs. 30,000 and it increased to Rs. 36,000, the percentage increase = ((36,000 – 30,000) ÷ 30,000) × 100 = (6,000 ÷ 30,000) × 100 = 20% increase.

How to Calculate Percentage Decrease

Percentage decrease works the same way but applies when a value goes down. Common uses include price drops, weight loss tracking, or measuring cost reductions.

% Decrease = ((Old Value – New Value) ÷ Old Value) × 100

Example: A product was priced at Rs. 5,000 but now costs Rs. 4,000. Decrease = ((5,000 – 4,000) ÷ 5,000) × 100 = 20% decrease.

Reverse Percentage – Finding the Original Value

Sometimes you know the final price after a percentage increase or decrease, and you want to find out what the original price was. This is called reverse percentage or back percentage calculation.

Original = Final Value ÷ (1 + Percentage/100) [if increased]
Original = Final Value ÷ (1 – Percentage/100) [if decreased]

Example: A product now costs Rs. 1,200 after a 20% increase. What was the original price? → 1,200 ÷ (1 + 20/100) = 1,200 ÷ 1.2 = Rs. 1,000.

How to Calculate Marks Percentage

Students often need to find their percentage score from total marks. The formula is straightforward and our calculator handles it automatically:

Score % = (Marks Obtained ÷ Total Marks) × 100

Example: You scored 450 out of 600 marks. Percentage = (450 ÷ 600) × 100 = 75%. This is particularly useful for calculating matric results, FSc results, university GPA conversions, and competitive exam scores.

Who Uses Percentage Calculators?

Common Percentage Calculations People Search For

Here are some everyday percentage problems our calculator can solve in seconds:

Tips to Calculate Percentages Mentally

While our calculator gives instant results, it helps to know some mental math tricks for quick estimates:

Our free online percentage calculator saves time when you need accurate results fast. Bookmark this page so you always have it handy for exams, shopping, business calculations, or any daily math task.

Frequently Asked Questions

To find X% of Y, use the formula: Result = (X ÷ 100) × Y. For example, 20% of 500 = (20 ÷ 100) × 500 = 100. You can also use our calculator above by entering the percentage and the number.
% Increase = ((New Value – Old Value) ÷ Old Value) × 100. If a product goes from Rs. 200 to Rs. 250, the increase is ((250–200)÷200)×100 = 25%.
Divide the part by the whole and multiply by 100. Example: 45 is what % of 180? = (45÷180)×100 = 25%. Use our "X is what % of Y" calculator above.
Use the formula: Percentage = (Marks Obtained ÷ Total Marks) × 100. If you got 420 out of 600, your percentage = (420÷600)×100 = 70%. Use the "Marks / Score Percentage" calculator above.
Reverse percentage helps you find the original value before a percentage change was applied. If a price is Rs. 1,200 after a 20% increase, original = 1,200 ÷ 1.2 = Rs. 1,000. Use our Reverse Percentage calculator for this.
Yes, completely free. No signup, no login, no downloads required. All 6 percentage calculators on this page work instantly in your browser on any device.