%NumberTools

Percentage Calculator

A professional, free, and mobile-friendly tool to solve all your percentage problems in seconds.

What is
% of
?
How to calculate percentage of a number?

Formula: (Percentage ÷ 100) × Number

Example: What is 20% of 150?

  • Convert 20% to decimal: 20 ÷ 100 = 0.2
  • Multiply by the number: 0.2 × 150 = 30
is what percent of
?
%
How to calculate what percent one number is of another?

Formula: (Part ÷ Whole) × 100%

Example: 30 is what percent of 150?

  • Divide part by whole: 30 ÷ 150 = 0.2
  • Multiply by 100: 0.2 × 100 = 20%
What is the percentage increase/decrease?
from
to
?
%
How to calculate percentage change?

Formula: ((New - Old) ÷ |Old|) × 100%

Example: Price changed from $50 to $75.

  • Difference: 75 - 50 = 25
  • Divide by old value: 25 ÷ 50 = 0.5
  • Convert to %: 0.5 × 100 = 50% increase
What is the value of percentage increase?
increased by
% is
How to increase a number by a percentage?

Formula: Value × (1 + Percentage ÷ 100)

Example: Increase 100 by 20%

  • Convert 20% to decimal: 0.2
  • Add 1: 1 + 0.2 = 1.2
  • Multiply: 100 × 1.2 = 120
What is the value of percentage decrease?
% off
is
How to decrease a number by a percentage?

Formula: Value × (1 - Percentage ÷ 100)

Example: Decrease 100 by 20%

  • Convert 20% to decimal: 0.2
  • Subtract from 1: 1 - 0.2 = 0.8
  • Multiply: 100 × 0.8 = 80

Everything You Need to Know About Percentages

Percentages are everywhere in our daily lives—from calculating the tip at a restaurant to understanding stock market fluctuations or determining the discount on a sale item. Our Percentage Calculator is designed to be the simplest and most accurate tool for handling these calculations instantly. Whether you're a student, a business professional, or just trying to figure out how much you saved on Black Friday, this tool has you covered.

How to Calculate "What Percent is X of Y"

This calculation answers the question: "20 is what percent of 50?". It helps you understand the proportion of a part relative to a whole.

Common Uses

  • Calculating test scores (45/50 correct)
  • Determining market share
Formula: (Part / Whole) × 100 = Percentage

Example: You answered 40 questions correctly out of 50 on a test.
Step 1: Divide 40 by 50 → 0.8
Step 2: Multiply by 100 → 80%

How to Find a Percentage of a Number

This helps you find a specific portion of a total amount. For example: "What is 15% of 200?".

Common Uses

  • Calculating tips at restaurants
  • Finding sales tax amounts
Formula: (Percentage ÷ 100) × Whole = Result

Example: Calculate a 20% tip on a $50 bill.
Step 1: Divide 20 by 100 → 0.2
Step 2: Multiply 0.2 by 50 → $10

Calculating Percentage Increase or Decrease

Use this to track changes over time, such as price inflation, weight loss, or investment growth.

Common Uses

  • Stock market gains/losses
  • Tracking weight loss progress
Formula: ((New Value - Old Value) ÷ |Old Value|) × 100

Example (Increase): A stock goes from $100 to $120.
Step 1: 120 - 100 = 20
Step 2: (20 ÷ 100) × 100 = 20% Increase

How to Increase a Number by a Percentage

This helps you find the final value after adding a percentage. Great for calculating total costs with tax.

Common Uses

  • Final price with sales tax
  • Salary raise calculations
Formula: Initial Value × (1 + (Percentage ÷ 100))

Example: $50 item with 8% sales tax.
Step 1: 8 ÷ 100 = 0.08
Step 2: 1 + 0.08 = 1.08
Step 3: 50 × 1.08 = $54.00

How to Decrease a Number by a Percentage

Use this to find the final price after a discount or markdown.

Common Uses

  • Calculating sale prices (20% OFF)
  • Depreciation of value
Formula: Initial Value × (1 - (Percentage ÷ 100))

Example: $100 shirt is 25% OFF.
Step 1: 25 ÷ 100 = 0.25
Step 2: 1 - 0.25 = 0.75
Step 3: 100 × 0.75 = $75.00