Percentage Calculator

Find a percentage of a number, what percentage one number is of another, percentage difference, or percentage change (increase or decrease), with steps.

Available Calculators

What is % of ?

Calculate a percentage of a given number

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is what % of ?

Find what percentage one number is of another number

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Percentage Difference

Calculate the relative difference between two values

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Percentage Change (Increase/Decrease)

Calculate the percentage increase or decrease from one value to another

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What is a Percentage?

A percentage is a way of expressing a number as a fraction of 100. It is denoted using the percent sign (%). For example, 30% means 30 out of 100, or 30/100, which equals 0.3. Percentages are widely used in everyday life, from calculating discounts and taxes to understanding statistics and data analysis.

Percentage Formula

The basic percentage formula is:

Percentage = (P ÷ W) × 100

where P = Part and W = Whole

Percentage Difference Formula

Percentage difference measures the relative difference between two values:

Percentage Difference = ((|V_1 - V_2|) ÷ (((V_1 + V_2) ÷ 2))) × 100

where V₁ and V₂ are the two values

Percentage Change Formula

Percentage change calculates the increase or decrease from an old value to a new value:

Percentage Change = ((V_new - V_old) ÷ V_old) × 100

where Vnew = New Value and Vold = Old Value

Examples of Percentage Calculations

Here are several everyday situations that show how easy it is to use our percentage calculator.

Example 1: VAT on a Product

A shop in London sets the net price of a jacket at £129.50. On top of this, customers must pay 20% VAT (Value Added Tax).

You can use our calculator by entering:

What is 20% of 129.50?

The calculator returns: £25.90

129.50 × 0.20 (20% as a decimal) = 25.90
Final price: 129.50 + 25.90 = £155.40

The formula used is:

129.50 × (20 ÷ 100) = 25.90

Example 2: UK General Election Turnout

In a UK parliamentary constituency, 75,000 people are registered to vote. On election day, 48,000 people actually cast their votes.

You can use our calculator by entering:

What percentage is 48,000 out of 75,000?

The calculator returns: 64%

48,000 ÷ 75,000 = 0.64
0.64 × 100 = 64%

The formula used is:

(48,000 ÷ 75,000) = 0.64 arrow 64%

Example 3: UK Savings Account Goal

A UK saver wants to earn at least £600 in interest per year. Their bank offers a 1.5% annual interest rate on a savings account.

You can use our calculator by entering:

£600 is 1.5% of what amount?

The calculator returns: £40,000

Convert 1.5% to decimal: 1.5% = 0.015
600 ÷ 0.015 = £40,000

The formula used is:

(600 ÷ 0.015) = 40,000

Example 4: UK Salary Increase

An employee in Manchester is told that, starting next month, they will receive a 5% pay rise. Their current monthly salary is £2,800.

You can use our calculator by entering:

Increase 2,800 by 5%

The calculator returns: £2,940

2,800 × 0.05 = 140
2,800 + 140 = £2,940

The formula used is:

2,800 + (2,800 × 0.05) = 2,940

Example 5: UK Business Profit Change

A UK business earns a profit of £85,000 in its first year. For the second year, the profit rises to £102,000.

You can use our calculator by entering:

By what percentage did the profit change?

The calculator returns: 20% increase

Absolute increase: 102,000 − 85,000 = 17,000
17,000 ÷ 85,000 = 0.20
0.20 × 100 = 20%

The formula used is:

((102,000 - 85,000) ÷ 85,000) × 100 = 20%

Example 6: UK Store Discount

A TV at Currys has a regular price of £299. The store runs a Black Friday promotion and offers a 20% discount.

You can use our calculator by entering:

What is 20% of 299?

The calculator returns: £59.80 discount, final price: £239.20

299 × 0.20 = £59.80 (discount amount)
299 − 59.80 = £239.20 (discounted price)

The formula used is:

299 × 0.20 = 59.80

Example 7: West End Theatre Occupancy

A West End theatre in London has 450 seats. For a popular Saturday evening show, 405 seats are occupied.

You can use our calculator by entering:

405 is what percent of 450?

The calculator returns: 90%

405 ÷ 450 = 0.9
0.9 × 100 = 90%

The formula used is:

(405 ÷ 450) × 100 = 90%

Example 8: GCSE Exam Scores

A student takes a GCSE exam with a maximum of 100 marks. They score 78 marks.

You can use our calculator by entering:

What is the percentage score?

The calculator returns: 78%

78 ÷ 100 = 0.78
0.78 × 100 = 78%

The formula used is:

(78 ÷ 100) × 100 = 78%

Example 9: Price Comparison Between UK Retailers

The same laptop costs £799 at John Lewis and £949 at PC World. You want to know the percentage difference between the two prices.

You can use our calculator by entering:

What is the percentage difference between £799 and £949?

The calculator returns: 17.14%

Difference: |799 − 949| = 150
Average: (799 + 949) ÷ 2 = 874
Percentage Difference: (150 ÷ 874) × 100 = 17.14%

The formula used is:

((|799 - 949|) ÷ (((799 + 949) ÷ 2))) × 100 = 17.14%

Example 10: UK Temperature Variation

On Monday, the temperature in Birmingham was 16°C. On Tuesday, it dropped to 10°C. Calculate the percentage difference.

You can use our calculator by entering:

What is the percentage difference between 16°C and 10°C?

The calculator returns: 46.15%

Difference: |16 − 10| = 6
Average: (16 + 10) ÷ 2 = 13
Percentage Difference: (6 ÷ 13) × 100 = 46.15%

The formula used is:

((|16 - 10|) ÷ (((16 + 10) ÷ 2))) × 100 = 46.15%

Example 11: UK City Population Comparison

Birmingham has a population of 1.1 million, while Manchester has 550,000 residents. Compare the two cities using percentage difference.

You can use our calculator by entering:

What is the percentage difference between 1,100,000 and 550,000?

The calculator returns: 66.67%

Difference: |1,100,000 − 550,000| = 550,000
Average: (1,100,000 + 550,000) ÷ 2 = 825,000
Percentage Difference: (550,000 ÷ 825,000) × 100 = 66.67%

The formula used is:

((|1,100,000 - 550,000|) ÷ (((1,100,000 + 550,000) ÷ 2))) × 100 = 66.67%

Example 12: A-Level Exam Score Comparison

Two students take the same A-Level exam. Student A scores 72 marks, while Student B scores 85 marks.

You can use our calculator by entering:

What is the percentage difference between 72 and 85?

The calculator returns: 16.56%

Difference: |72 − 85| = 13
Average: (72 + 85) ÷ 2 = 78.5
Percentage Difference: (13 ÷ 78.5) × 100 = 16.56%

The formula used is:

((|72 - 85|) ÷ (((72 + 85) ÷ 2))) × 100 = 16.56%

Summary

These examples show how our percentage calculator can handle:

  • •Finding a percentage of a number (VAT, discounts, interest)
  • •Finding what percentage one value is of another (voter turnout, exam scores, occupancy)
  • •Finding the original amount or the percentage change (profits, salary changes, investment goals)
  • •Calculating percentage difference between two values (price comparisons, temperature variations, population differences)

You can adapt any real-life situation to one of these patterns and let the calculator do the work for you.

How to Use

  1. Select the type of percentage calculation you need (percentage of, what percentage, percentage difference, or percentage change).
  2. Enter the required values in the input fields. The calculator will automatically update results in real-time.
  3. View the result and step-by-step calculation breakdown with formulas displayed using mathematical notation.

Frequently asked questions

How do I calculate a percentage?

To calculate a percentage, divide the part by the whole and multiply by 100. For example, if you have 30 out of 100, the percentage is (30/100) × 100 = 30%.

Can I calculate percentage increase or decrease?

Yes, our calculator supports percentage increase, decrease, and difference calculations. Simply select the appropriate calculator type and enter your values.

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About this tool

Published by Online Tools Center

Last updated:

Check the units, assumptions and rounding before using a result. Health and financial estimates are educational and do not replace individual professional advice.

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