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Percentage Calculator

Instantly calculate percentages with ease. Whether you're shopping, studying, budgeting, or working with data, our simple and fast percentage calculator is here to help.

Use the forms below to perform different types of percentage calculations. Find percentage of a number, Calculate what percent one number is of another, Work out percentage increase or decrease, Solve for the original amount before a percentage change, Reverse percentage, proportions, and more.

What is X% of Y?

Percentage of a Number
calculates a specific percentage of a given value.

Examples:
  • 20% of 150 = 30
  • 5% of 1200 = 60
Tips:
  • Useful for tips, discounts, commissions, etc.

What Percentage is X of Y?

Percentage Proportion
Determines what percentage one number is of another.

Examples:
  • 30 is 25% of 120
  • 45 is 15% of 300
Tips:
  • Useful for proportions, test scores, etc.

X is Increased by Y%

Percentage Change
Measures how much a value has increased in percentage terms.

Examples:
  • 100 increased by 10% = 110
  • 25 increased by 20% = 30
Tips:
  • Useful for price raises, growth, markups, etc.

X is Decreased by Y%

Percentage Change
Measures how much a value has decreased in percentage terms.

Examples:
  • 20 decreased by 25% = 5
  • 50 decreased by 10% = 45
Tips:
  • Useful for discounts, depreciation, etc.

What is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. The word itself comes from the Latin "per centum," meaning "by the hundred." It is denoted using the % symbol. For example, 45% means 45 out of 100.

Basic Formula

To find the percentage of a number, use:

(Percentage / 100) x Total Number Examples

Example: What is 20% of 150?

(20 / 100) x 150 = 30

Example: What is 25% of 100?

(25 / 100) x 100 = 25

Example: What is 75% of 200?

(75 / 100) x 200 = 150

Why Use Percentages?

  • Standardize comparisons: Percentages help compare values with different bases.
  • Simplify communication: Saying "90% complete" is clearer than "27 of 30 complete."
  • Reveal trends: Great for understanding growth, inflation, or profit changes.
  • Shopping discounts calculations
  • Tax and tips calculation
  • Survey results
  • Battery life, progress bars

Types of Percentage Problems

  1. Finding the percentage of a number
    Example: 10% of 80 = (10 / 100) x 80 = 8
  2. Finding what percent one number is of another
    Example: 10 is what percent of 50?
    (10 / 50) x 100 = 20%
  3. Finding the whole when percentage and part are known
    Example: 25 is 20% of what?
    25 / (20 / 100) = 125

Daily Examples

  1. Shopping Discount:
    25% off $80 = (25 / 100) x 80 = 20 You save $20.
  2. Exam Score:
    42 out of 60 = (42 / 60) x 100 = 70%
  3. Interest Rate:
    5% interest on $1000 = (5 / 100) x 1000 = 50 You earn $50 in a year.

Tips for Quick Mental Calculation

  • 10% = move decimal one place left
  • 5% = 10% / 2
  • 1% = divide by 100

Visualizing Percentages

Imagine a pie chart with 100 slices:

  • 1% = one slice
  • 25% = 25 slices
  • 100% = full pie

Percentage Calculation Methods

1. Percentage of a Number

Use when: You know the percentage and total number, and want to find the part.

Formula:
(Percentage / 100) x Total

Example: 20% of 200 = (20 / 100) x 200 = 40

Want to learn more? Visit Percentage of a Number.

2. What Percent One Number Is of Another

Use when: You have two numbers and want to know what percent one is of the other.

Formula:
(Part / Total) x 100

Example: 10 is what percent of 50? (10 / 50) x 100 = 20%

Want to learn more? Visit Percentage of a Number.

3. Finding the Total from a Percentage

Use when: You know the part and the percentage, and want to find the total.

Formula:
Total = Part / (Percentage / 100)

Example: 25 is 20% of what number? 25 / (20 / 100) = 125

→ How to Find the Total from a Percentage Guide

4. Percentage Increase or Decrease

Use when: You're comparing how much a number has changed.

Formula:
((New - Original) / Original) x 100

Example (Increase): 100 → 120: (120 - 100) / 100 x 100 = 20%

→ Percentage Increase Method

Example (Decrease): 100 → 80: (100 - 80) / 100 x 100 = 20%

→ Percentage Decrease Method

5. Reverse Percentage

Use when: You know the result after a percentage change and want to find the original.

Formula (Increase):
Original = Final / (1 + Percentage / 100)

Formula (Decrease):
Original = Final / (1 - Percentage / 100)

Example:
$120 after 20% increase → 120 / 1.20 = 100

→ How to Solve Reverse Percentage Problems

6. Percent per Unit Method

Use when: You're calculating based on one unit (e.g., per person, per item).

Example:
5 out of 20 students got A: (5 / 20) x 100 = 25%

→ How to Use the Percent per Unit Method

7. Proportional (Ratio-Based) Method

Use when: You prefer to solve by setting up a proportion.

Example:
15 is 30% of what number?
30 / 100 = 15 / x → x = (15 x 100) / 30 = 50

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