Percentage Calculator

What is ___ % of ___?
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This calculation isn’t possible with the numbers entered (check for zero where division is needed).
Estimate shown to 4 decimal places where relevant.

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What This Tool Does

This calculator solves the three most common percentage problems: finding what percentage one number is of another, calculating the difference between two values as a percentage, and working out how much a value has increased or decreased. Enter any two known values and it returns the third — no manual formula rearranging needed.

How It’s Calculated

All percentage problems come down to one core relationship:

P × V1 = V2

Where P is the percentage, V1 is the base value, and V2 is the result.

Worked Example:

  • What is 5% of 30?
  • 0.05 × 30 = 1.5

Flip it: 1.5 is what percent of 30?

  • 1.5 ÷ 30 = 0.05 × 100 = 5%

The same relationship works in all three directions depending on which value is missing. When solving manually, remember to convert your percentage to decimal form first by dividing by 100.

Percentage Difference

Use this when comparing two values where neither is clearly the “original” — for example, comparing the price of two products.

Formula: |V1 − V2| ÷ ((V1 + V2) ÷ 2) × 100

Example: Difference between 10 and 6

  • |10 − 6| = 4
  • (10 + 6) ÷ 2 = 8
  • 4 ÷ 8 × 100 = 50%

Percentage Change

Use this when one value clearly comes before the other — a salary increase, a price drop, a test score improvement.

Formula: (New − Old) ÷ Old × 100

To apply a percentage increase or decrease to a number directly:

  • Increase: Original × (1 + rate) → 500 × 1.10 = 550
  • Decrease: Original × (1 − rate) → 500 × 0.90 = 450

Edge Cases and Special Rules

Percentage of a percentage: Convert both to decimals before multiplying. 20% of 50% = 0.20 × 0.50 = 0.10 = 10%. Skipping the conversion is a common error.

Difference vs. change: Percentage difference uses the average of two values as the base and has no direction. Percentage change uses the starting value as the base and gives a direction — increase or decrease.

Zero as a base: Percentage change is undefined when the original value is zero. The calculator will not return a result in this case.

Negative numbers: Percentages can apply to negative values such as temperatures or financial losses, but pay close attention to signs when reading results.

Who Uses This

  • Students calculating marks, grades, or CGPA conversions
  • Shoppers working out discounts, markups, or sale savings
  • Business owners tracking profit margins, revenue growth, or cost changes
  • Finance professionals comparing returns, price movements, or budget variances
  • Anyone using Excel who wants to verify a percentage formula before building it into a spreadsheet

Percentage vs. Percentile

These two terms are often confused but measure different things. A percentage expresses a part of a whole — you scored 80% on a test. A percentile shows rank within a group — you scored higher than 80% of all test-takers. The numbers can coincidentally match but they carry entirely different meanings.

FAQ

How do I calculate the percentage of marks?

Divide marks obtained by total marks, then multiply by 100. Example: 420 out of 500 = 420 ÷ 500 × 100 = 84%.

What is the difference between percentage difference and percentage change?

Percentage difference compares two values with no set starting point, using their average as the base. Percentage change always has a starting value and an ending value, and shows direction — increase or decrease.

How do I calculate a percentage increase?

Subtract the original value from the new value, divide by the original, then multiply by 100. Example: 80 to 100 → (100 − 80) ÷ 80 × 100 = 25% increase.

How do I calculate profit percentage?

Divide profit (selling price minus cost price) by cost price, then multiply by 100. Example: cost ₹400, sold for ₹500 → profit ₹100 → 100 ÷ 400 × 100 = 25%.

Can I use this for CGPA to percentage conversion?

This tool handles general percentage math. For CGPA conversion, multiply your CGPA by your university’s official conversion factor — commonly 9.5 or 10, depending on the institution.

A Note on Results

Enter any two known values above and the calculator returns the third instantly. All results are for general reference — double-check critical figures related to finance, tax, or academic records against official sources.