Percentage Calculator

Percentage Calculator

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Nishadh Mohammed updated on 7 March 2025

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Table of Contents
  • What is a Percentage?
  • How to Calculate a Percentage?
  • How is a Percentage Used?
  • How do I calculate a percentage increase?
  • How do I calculate a percentage decrease?
  • How do I calculate a reverse percentage?
  • How to Convert a Percentage to a Grade?
  • How to Calculate a GPA from a Percentage?

Percentages are a quick way to compare numbers, track changes, and understand proportions. Whether you’re working out a sale discount, checking your exam scores, or comparing mortgage rates, understanding percentages makes life easier.

But what is a percentage? How do you calculate it? You can do it manually with a simple formula or use our online percentage calculator to get results in seconds — perfect for when you need a quick answer without the maths! Read on to find out more in our detailed guide.

What is a Percentage?

A percentage expresses a number as a fraction of 100. It’s often used to compare proportions, measure changes, and analyse statistics. You’ll see percentages in finance, retail, education, and health data.

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What is a percentage?

How to Calculate a Percentage?

To calculate a percentage, use this simple formula:

Percentage = (Part​ ÷ Total) × 100

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How is a Percentage Used?

Percentages are a part of everyday life, helping us understand proportions, compare values, and make smarter financial decisions. Here are some real-life examples of how percentages are used:

Shopping: Discounts & Sales

Imagine you find a coat on sale for 25% off its original price of £100. To find your savings:

  • Multiply the discount percentage by the original price: 100 × 0.25 = 25
  • You save £25, and the new price is £75.

Sales and discounts use percentages to show how much you save at checkout.

Finance: Mortgage & Savings Rates

Percentages are essential in banking, especially for interest rates on mortgages and savings accounts.

If your bank offers 3% interest on a £5,000 savings account:

  • Multiply your balance by the interest rate: 5000 × 0.03 = 150
  • You earn £150 in interest for the year.

The higher the percentage, the more you earn on savings!

Health & Nutrition: Food Labels

Ever checked a food label and seen “10% sugar” on a fruit juice bottle? This means that in 100ml of juice, 10ml is sugar.

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Understanding percentages in nutrition helps you make healthier choices. From calculating tips at restaurants to tracking sports statistics, percentages are everywhere!

How do I calculate a percentage increase?

A percentage increase tells you how much something has grown compared to its original value.

Formula:

Percentage Increase = ((New Value − Old Value​) ÷ Old Value) × 100

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How do I calculate a percentage increase?

How do I calculate a percentage decrease?

A percentage decrease tells you how much something has reduced from its original value.

Formula:

Percentage Decrease = ((Old Value − New Value​) ÷ Old Value) × 100

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How do I calculate a percentage decrease?

How do I calculate a reverse percentage?

A reverse percentage helps you find the original value before a percentage change.

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How to Convert a Percentage to a Grade?

In the UK, GCSE and A-Level grades are sometimes converted to percentages for UCAS applications.

PercentageGCSE GradeA-Level Grade
90-100%9 (A*)A*
80-89%8 (A)A
70-79%7 (A)B
60-69%5-6 (B/C)C
Below 60%4 or lowerD/E
Percentage to grade conversion examples
90-100%
GCSE Grade
9 (A*)
A-Level Grade
A*
80-89%
GCSE Grade
8 (A)
A-Level Grade
A
70-79%
GCSE Grade
7 (A)
A-Level Grade
B
60-69%
GCSE Grade
5-6 (B/C)
A-Level Grade
C
Below 60%
GCSE Grade
4 or lower
A-Level Grade
D/E
Percentage to grade conversion examples
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How to Calculate a GPA from a Percentage?

In the UK, students don’t use GPA like in the US, but universities may convert grades to a GPA scale for international applications.

PercentageUK GradeApproximate GPA (US Scale)
70%+First (1st)4.0
60-69%Upper Second (2:1)3.3 - 3.7
50-59%Lower Second (2:2)2.7 - 3.0
40-49%Third (3rd)2.0 - 2.5
Below 40%Fail0.0 - 1.5
Percentage to GPA calculation example
70%+
UK Grade
First (1st)
Approximate GPA (US Scale)
4.0
60-69%
UK Grade
Upper Second (2:1)
Approximate GPA (US Scale)
3.3 - 3.7
50-59%
UK Grade
Lower Second (2:2)
Approximate GPA (US Scale)
2.7 - 3.0
40-49%
UK Grade
Third (3rd)
Approximate GPA (US Scale)
2.0 - 2.5
Below 40%
UK Grade
Fail
Approximate GPA (US Scale)
0.0 - 1.5
Percentage to GPA calculation example
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Nishadh Mohammed
Nishadh Mohammed is a seasoned news editor and financial writer, working with HelloSafe since May 2023. Nishadh has developed expertise in financial markets, insurance, and investment products, with a deep understanding of the Canadian financial landscape. He has honed his SEO skills and content marketing strategies while writing for Canadian publishing houses. Armed with a master's in Business Analytics and extensive journalistic experience, Nishadh uniquely combines data proficiency and thorough research to deliver comprehensive and accessible information.

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