This percentage calculator includes the core formulas used in exams, finance, and analytics—X% of Y, what percent, increase/decrease, and percentage difference—with instant visual feedback.

Percentage Calculator

Calculate what is X% of Y, what percent X is of Y, percentage increase or decrease, and add or subtract a percentage. Results update as you type.

What is X% of Y?

Result = (X ÷ 100) × Y

What is% of

X is what % of Y?

Result = (X ÷ Y) × 100

is what % of

Percentage Increase

((new − old) ÷ old) × 100

OldNew

Percentage Decrease

((old − new) ÷ old) × 100

OldNew

Percentage Difference

|a − b| ÷ ((a + b) ÷ 2) × 100

and

Add Percentage

value + (value × percent ÷ 100)

+%

Subtract Percentage

value − (value × percent ÷ 100)

−%

How to Use

Enter numbers in the fields above. You can tab between fields or click Calculate. Results appear instantly. Use Reset to clear all tools.

Percentage Formulas

  • What is X% of Y: (X/100) × Y
  • X is what % of Y: (X/Y) × 100
  • Increase: ((new − old)/old) × 100
  • Decrease: ((old − new)/old) × 100
  • Difference: |a−b| / ((a+b)/2) × 100
  • Add %: value + (value × percent/100)
  • Subtract %: value − (value × percent/100)

Examples

  • What is 20% of 150? → (20/100) × 150 = 30
  • 30 is what % of 150? → (30/150) × 100 = 20%
  • Price increased from 50 to 75 → ((75−50)/50) × 100 = 50% increase

Frequently Asked Questions

Multiply Y by X and divide by 100. Formula: (X/100) × Y. Example: What is 20% of 150? (20/100) × 150 = 30.

Key Terms

Percentage
A ratio out of 100 used to express share, increase, or decrease.
Base value
Reference number against which percentage is calculated.
Percentage point
Absolute difference between two percentages (not the same as percent change).

Benefits of This Calculator

  • Immediate what-if analysis for percentage changes and comparisons.
  • Formula transparency with examples and FAQs on each calculator page.
  • Works directly in browser with no sign-up or data upload required.

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