Save some mental load with help from our percentage calculator
Percentage Calculator Tool
Whether you are working out a discount in a sale, calculating VAT, or analysing data for a report, percentages are an essential part of daily life. Our free Percentage Calculator makes it simple to handle any calculation instantly.
Stop struggling with complex formulas. Just enter your numbers below, and let our tool do the work for you.
How to Calculate Percentages
A percentage is simply a number or ratio expressed as a fraction of 100. It is denoted using the percent sign, “%”. Understanding how to calculate them is useful for everything from tipping at a restaurant to figuring out interest rates.
1. How to Find the Percentage of a Number
This is the most common calculation. To find a percentage of a number, you convert the percentage to a decimal and multiply it by the number.
Formula: (Percentage / 100) × Total Value
Example: To find 20% of £500:
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Divide 20 by 100 to get 0.2.
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Multiply 0.2 by 500.
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Result: £100.
2. How to Calculate Percentage Increase and Decrease
Knowing how to calculate percentage change is vital for tracking business growth, price changes, or weight loss.
Formula for Percentage Increase/Decrease: ((New Value - Old Value) / Old Value) × 100
Example (Percentage Increase): A product price goes from £40 to £50.
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Subtract the old value from the new value: 50 – 40 = 10.
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Divide that difference by the old value: 10 / 40 = 0.25.
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Multiply by 100: 0.25 × 100 = 25.
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Result: A 25% increase.
3. How to Calculate What Percentage One Number is of Another
This is useful when you want to see what portion of a whole a specific number represents.
Formula: (Part / Whole) × 100
Example: You scored 45 out of 60 on a test. What is your percentage?
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Divide the part (45) by the whole (60): 45 / 60 = 0.75.
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Multiply by 100: 0.75 × 100 = 75.
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Result: You scored 75%.
Real-World Examples: When to Use a Percentage Calculator
Calculating VAT (Value Added Tax)
In the UK, the standard VAT rate is currently 20%. To add VAT to a price, you simply calculate a 20% increase.
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To add VAT: Multiply your net price by 1.2.
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To remove VAT: Divide the gross price by 1.2.
Working Out Discounts
Sales are everywhere. If a jacket costs £80 and has a 15% discount:
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Work out 15% of 80 (0.15 × 80 = £12).
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Subtract the discount from the original price (£80 – £12 = £68).
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New Price: £68.
Frequently Asked Questions (FAQs)
What is the formula for finding a percentage?
To find a percentage of a number, use the formula: (Value / Total Value) × 100. For example, if you want to know what percentage 20 is of 50, you calculate (20 / 50) × 100 = 40%.
How do I calculate a percentage increase?
To calculate a percentage increase, subtract the original number from the new number to find the difference. Then, divide this difference by the original number and multiply the result by 100.
How do I turn a fraction into a percentage?
To convert a fraction into a percentage, divide the top number (numerator) by the bottom number (denominator) and multiply the result by 100. For example, for the fraction 3/4, you calculate 3 ÷ 4 = 0.75, then 0.75 × 100 = 75%.
Can I calculate percentages without a calculator?
Yes, for simple numbers. A useful trick is to find 10% first (by moving the decimal point one place to the left) and then multiply or divide from there. For example, to find 30% of £50: Find 10% (£5), then multiply by 3 to get £15.
What is the reverse percentage calculation?
Reverse percentage is used to find the original quantity after a percentage increase or decrease has been applied. For example, finding the price before VAT was added. To do this, divide the final amount by (1 + percentage as a decimal). E.g., £120 / 1.2 = £100.
Why is calculating percentages important for business?
Percentages are crucial for analysing financial performance. They allow businesses to track profit margins, calculating markup, determine year-on-year growth, and understand market share. Using accurate tools like our calculator ensures these critical decisions are based on correct data.