How do you calculate 20% of a number?

Multiply the number by 0.20. Example: 20% of 150 = 150 × 0.20 = 30. Alternatively, use the formula: (20/100) × 150 = 30.

What's the quickest method to find percentage increase?

Use the formula: ((New - Old) / Old) × 100. Example: If a value increases from 50 to 60, the percentage increase is ((60 - 50) / 50) × 100 = 20%.

Why do shops use percentage discounts instead of fixed amounts?

Percentage discounts feel larger and more appealing, even when the actual savings are similar. They also scale well across product ranges and are easier to compare.

What is a reverse percentage?

Reverse percentage helps find the original value when you only know the final value after a percentage change. For example, if 120 is 20% more than the original, the original value is 120 ÷ 1.20 = 100.

How are percentages used in taxes globally?

Tax systems like GST, VAT, and sales tax use fixed percentages to calculate the payable amount on goods and services. For example, 18% GST on ₹2,000 = (18/100) × 2,000 = ₹360.

What is the difference between percent and percentage points?

Percent is relative change, while percentage points measure the difference between two percentages. Example: 10% → 12% is a 2 percentage point increase, but a 20% relative increase.

Why does percentage difference use the average of two values?

Using the average ensures fair comparison without assuming one number is the base value. This is essential in statistics and scientific analysis where neither value should be treated as the reference.

How accurate is the Percentage Calculator?

The calculator provides precise results up to multiple decimal places and follows universally accepted mathematical formulas for all percentage operations.

Can I use this calculator for financial planning?

Yes. It's ideal for calculating interest, inflation impact, taxes, salary hikes, savings growth, discounts, and more.

Is percentage calculation the same in every country?

Yes. Percentages follow a universal mathematical definition, making them consistent globally across all applications and industries.

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Percentage Calculator: Quick & Accurate % Online

Fast, accurate Percentage Calculator for percent increase, percent decrease, difference, reverse percentage, and all % calculations in one easy tool.

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What Is This Calculator?

A Percentage Calculator is an online tool that helps you quickly compute any type of percentage-related value, such as finding a percentage of a number, calculating percent increase or decrease, comparing two values, or reversing a percentage to get the original amount. It eliminates manual calculations and provides instant, accurate results for students, professionals, shoppers, and anyone dealing with numbers in daily life.

Basic Formula

Percentage = (Part / Whole) × 100

Understanding Percentage Concepts

Percentages are everywhere: discounts, marks, profits, taxes, salary raises, interest rates, analytics, and statistics. This section explains each concept clearly and simply.

What Is a Percentage?

A percentage (%) expresses a number as a part of 100. It answers: How much out of 100?

If a student scores 45 out of 60, the percentage is: (45/60) × 100 = 75%

Percentages help compare values on a uniform scale.

The Basic Percentage Formula

The core formula behind all percentage calculations is:

Value = (Percentage / 100) × Total

20% of 200 = (20/100) × 200 = 40

What Is Percentage Increase?

Percentage increase shows how much a value has grown relative to the original number.

Percentage Increase = ((New Value - Original Value) / Original Value) × 100

A salary goes from ₹30,000 to ₹36,000: ((36,000 - 30,000) / 30,000) × 100 = 20%

What Is Percentage Decrease?

Percentage decrease shows how much a value has reduced relative to the original.

Percentage Decrease = ((Original Value - New Value) / Original Value) × 100

A product price drops from $50 to $40: ((50 - 40) / 50) × 100 = 20%

What Is Percentage Difference?

Percentage difference compares two values without choosing one as the base.

Percentage Difference = (|A - B| / ((A + B) / 2)) × 100

Comparing 80 and 100: (20 / 90) × 100 ≈ 22.22%

Used in statistics, analytics, and scientific measurements.

How to Reverse a Percentage

Reverse percentage finds the original value before applying a percentage.

Original Value = Final Value / (1 + (Percentage / 100))

If 120 is 20% more than the original: 120 / 1.20 = 100

Real-Life Usage of Percentages

Percentages are essential in:

Finance: interest rates, tax, investment growth
Shopping: discounts, savings, offers
Education: exam scores, grade calculations
Business: profit/loss, revenue change
Statistics: data comparison, growth metrics
Healthcare: dosage percentages, body measurements

Percentages simplify numerical comparisons, making them one of the most universal mathematical tools.

How to Use the Percentage Calculator (Step-by-Step Guide)

Follow these simple steps depending on your calculation mode:

Choose a tab from the calculator options (e.g., 'What is X% of Y?', '% Increase', or 'Reverse %').
Enter the required values in the input fields.
The calculator instantly processes your inputs and gives a clear final answer.
View the formula breakdown below the result to understand how the answer was derived.
If needed, switch to another tab to perform a different percentage-related calculation.

The tool is designed to be intuitive for everyone, from school children to working professionals.

Example Scenarios

1. Salary Increase Example

Your monthly salary increases from $2,500 to $3,000.

Percentage increase: ((3000 - 2500) / 2500) × 100 = 20%

So, your salary increased by 20%.

2. Shopping Discount Example

A jacket originally costs $80 and has a 35% discount.

Discount amount: (35/100) × 80 = 28

Final price: 80 - 28 = 52

You pay $52 after discount.

3. Tax Percentage Example

A product priced at ₹2,000 has an 18% GST.

GST amount: (18/100) × 2000 = 360

Final cost: 2000 + 360 = 2360

Total payable: ₹2,360

4. Student Marks Example

A student scores 72 out of 90.

Percentage: (72/90) × 100 = 80%

The student scored 80%.

Formulas

Basic Percentage Formula

Percentage = (Part / Total) × 100

Find X% of Y

Value = (X / 100) × Y

Percentage Increase

(New - Original) / Original × 100

Percentage Decrease

(Original - New) / Original × 100

Percentage Difference

|A - B| / ((A + B) / 2) × 100

Reverse Percentage

Original Value = Final Value / (1 ± (Percentage / 100))

Use + for increase and - for decrease.

Final Value After % Change

Final = Initial × (1 ± Percentage / 100)

Interactive Mini Cheat-Sheet

%	Decimal	Fraction
5%	0.05	1/20
10%	0.10	1/10
12.5%	0.125	1/8
25%	0.25	1/4
50%	0.50	1/2
75%	0.75	3/4
100%	1.00	1

Quick Tips for Percentage Calculations

To find 10% of any number, simply move the decimal point one place to the left. Example: 10% of 250 = 25
To find 50%, divide the number by 2. It's the fastest mental math shortcut.
To calculate percentage increase: subtract original from new, divide by original, then multiply by 100.
To calculate percentage decrease: subtract new from original, divide by original, then multiply by 100.
When comparing two values, percentage difference uses the average of both values as the base.
Reverse percentage requires dividing, not subtracting. If 120 is 20% more, original = 120 ÷ 1.20 = 100

Conclusion

The Percentage Calculator is an essential tool for anyone dealing with numbers in everyday life. Whether you're calculating discounts while shopping, analyzing financial data, tracking exam scores, or planning budgets, this calculator simplifies complex percentage operations into instant, accurate results.

By understanding the formulas and concepts behind percentage calculations, you gain valuable mathematical literacy that applies across education, finance, business, and personal decision-making. Bookmark this tool and use it whenever you need quick, reliable percentage calculations.

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Written by

Amit Kulkarni

Founder & Editor-in-Chief

Software engineer with 7 years of experience building accurate, reliable calculators. Committed to providing expert-verified tools for finance, health, education, and utilities.