Percentage Calculator — Quick & Easy Percentage Calculations

Calculate percentages instantly with four different modes. No sign-up, no formulas to remember.

Last updated: March 2026

What is % of ?
750
is what % of ?
15%
From to
50% increase
%
1,200

How to Use This Percentage Calculator

This free percentage calculator gives you instant answers for the four most common percentage questions. No formulas to memorise and no sign-up required. Here is how each mode works:

  1. X% of Y — Enter a percentage and a number to find the result. For example, enter 18 and 500 to find that 18% of 500 is 90. Great for calculating GST, tips, or discounts.
  2. X is what % of Y — Enter two numbers to find what percentage the first is of the second. Useful for calculating exam scores: if you scored 420 out of 500, enter 420 and 500 to get 84%.
  3. Percentage Change — Enter an original value and a new value. The calculator tells you the percentage increase or decrease. Perfect for tracking price changes, salary hikes, or investment returns.
  4. Adjust by % — Enter a starting value, choose increase or decrease, and enter a percentage. The calculator returns the adjusted result. For instance, 1,000 increased by 20% gives 1,200.

All modes auto-calculate as you type, so results update in real time. Simply switch between tabs to use a different calculation mode.

Percentage Formulas Explained

Understanding the underlying formulas helps you solve percentage problems even without a calculator. Here are the four core formulas this tool uses:

1. Find X% of Y

Result = (X / 100) × Y

Divide the percentage by 100 to convert it to a decimal, then multiply by the number. For example, 15% of 5,000 = (15 / 100) × 5,000 = 750. This is the formula behind discount calculations, tax computations, and tip estimates worldwide.

2. X is What Percent of Y?

Percentage = (X / Y) × 100

Divide the part by the whole and multiply by 100. If you scored 420 marks out of 500, your percentage is (420 / 500) × 100 = 84%. This formula is essential for grade calculations, market share analysis, and budget tracking.

3. Percentage Increase or Decrease

% Change = ((New Value − Old Value) / Old Value) × 100

A positive result indicates an increase; a negative result indicates a decrease. For example, if a stock price moves from 200 to 250, the change is ((250 − 200) / 200) × 100 = 25% increase. This formula is used for salary hikes, inflation tracking, and year-over-year growth comparisons.

4. Increase or Decrease a Number by a Percentage

New Value = X × (1 ± Y/100)

Use the plus sign for an increase and the minus sign for a decrease. For example, 1,000 increased by 20% = 1,000 × 1.20 = 1,200. Similarly, 1,000 decreased by 20% = 1,000 × 0.80 = 800. Retailers use this formula to mark up or discount prices.

Practical Percentage Examples

Exam Marks

A student scores 456 out of 600 in their board exams. Their percentage is (456 / 600) × 100 = 76%. Use Mode 2 of the calculator above to verify this instantly.

Shopping Discounts

A jacket originally costs 2,500 and has a 30% discount. The discount amount is 30% of 2,500 = 750. The sale price is 2,500 − 750 = 1,750. Use Mode 1 to calculate the discount and Mode 4 to find the final price directly (2,500 decreased by 30%).

Salary Hike

Your annual salary is 6,00,000 and you receive a 12% raise. The new salary is 6,00,000 × 1.12 = 6,72,000. Use Mode 4 with "increased by 12%" to confirm. To find the percentage hike from an old salary to a new salary, use Mode 3.

Investment Returns

You invested 50,000 and it grew to 62,000 in one year. The return is ((62,000 − 50,000) / 50,000) × 100 = 24% increase. Enter 50,000 and 62,000 in Mode 3 to calculate this.

GST Calculation

An item costs 1,000 before GST. With 18% GST, the tax amount is 18% of 1,000 = 180, making the total 1,180. Use Mode 1 to find the GST amount, or Mode 4 to get the final price inclusive of tax.

Frequently Asked Questions

How do you calculate a percentage?

Divide the part by the whole, then multiply by 100. For example, 45 out of 60 is (45 / 60) × 100 = 75%. This works for exam scores, survey responses, task completion rates, and more.

What is the percentage formula?

The basic formula is Percentage = (Part / Whole) × 100. To find a specific percentage of a number, rearrange it to Result = (Percentage / 100) × Number.

How do you calculate percentage increase?

Use the formula: ((New Value − Old Value) / Old Value) × 100. If a price rises from 200 to 250, the increase is ((250 − 200) / 200) × 100 = 25%.

How do you find the percentage of marks?

Divide the marks obtained by the total marks and multiply by 100. For example, if a student scores 420 out of 500, the percentage is (420 / 500) × 100 = 84%. This method works whether the total is 500, 600, or any other number.

How do you convert a percentage to a decimal?

Divide the percentage by 100. For example, 75% becomes 0.75. To go the other way, multiply the decimal by 100: 0.45 × 100 = 45%. This conversion is necessary when using percentages in mathematical formulas or spreadsheets.

What is the difference between percentage difference and percentage change?

Percentage change measures the increase or decrease relative to an original value: ((New − Old) / Old) × 100. Percentage difference compares two independent values without labelling either as the original: (|A − B| / ((A + B) / 2)) × 100. Use percentage change when one value clearly came first (e.g. last year vs. this year). Use percentage difference when comparing two equivalent items (e.g. prices at two different stores).

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