Percentage Calculator

Solve common percentage problems, percent changes, and fraction conversions instantly

What is P% of X?

% of

Result: 30

X is what % of Y?

of

Result: 30%

Percentage Increase / Decrease (Change)

Initial Value (From)

Final Value (To)

Change: +35.00% Increase

Understanding Everyday Percentage Math

A percentage represents a fraction of 100. The term originates from the Latin per centum, meaning "by the hundred".

Percentage Formula: (Part / Whole) × 100 = Percentage %
Percentage Change Formula: [(New Value - Old Value) / |Old Value|] × 100

Frequently Asked Questions

How do I calculate a discount percentage?

Subtract the sale price from the original price, divide by the original price, and multiply by 100. For example: ($100 - $80) / $100 × 100 = 20% discount.

How to Use the Percentage Calculator

Select calculation mode: What is X% of Y, X is what % of Y, or Percentage Increase/Decrease.
Enter the corresponding numbers in the input boxes.
View the instant result, step-by-step mathematical fraction, and visual explanation.

Core Percentage Formulas

Find Percentage: Result = (Percentage / 100) × Value
Find Percentage Share: % = (Part / Whole) × 100
Percentage Change: % Change = [(New Value - Old Value) / Old Value] × 100

Practical Step-by-Step Example

Calculate 15% tip on an $80 restaurant bill:

Calculation: (15 / 100) × 80 = 0.15 × 80 = $12.00
Total bill with tip: $80 + $12 = $92.00