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Percentage Calculator

Calculate percentages, find what percentage one number is of another, and compute percentage change.

Three Calculation Modes

X% of Y, X is what % of Y, and % change

Step-by-Step Formula

See the exact calculation broken down

Financial Applications

Perfect for returns, discounts, and markups

Percentage Calculator

Choose a calculation mode and enter your values.

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How to Calculate Percentages

The Percentage Formula

X% of Y = (X / 100) x Y

X is what % of Y = (X / Y) x 100

% change = ((New - Old) / Old) x 100

These three formulas cover virtually every percentage calculation you will encounter, from calculating tips and discounts to analysing investment returns and business metrics.

Worked Examples

  • 15% of 300: (15/100) x 300 = 45
  • 75 is what % of 250: (75/250) x 100 = 30%
  • Change from 80 to 100: ((100-80)/80) x 100 = 25% increase

Common Percentage Calculations in Finance

Investment Returns

If your portfolio was worth £10,000 and is now £11,200, that is a 12% return: ((11,200 - 10,000) / 10,000) x 100 = 12%. Use percentage change to track gains and losses over any period.

Discounts and Markups

A £120 item with 25% off: 25% of 120 = £30, sale price = £90. A product costing £50 with 40% markup: 40% of 50 = £20, selling price = £70.

How to Use This Percentage Calculator

1

Choose Your Mode

Select from three percentage calculation types.

2

Enter Your Values

Type in the numbers you want to calculate.

3

Get Instant Answer

See the result with a step-by-step formula breakdown.

Percentage Tips and Shortcuts

  • 10% shortcut. To find 10% of any number, just move the decimal point one place left. 10% of 250 = 25. Then double for 20%, halve for 5%, etc.
  • Swap trick. 8% of 25 is the same as 25% of 8 (both = 2). If one calculation is easier, use it.
  • Percentage point vs percentage. An interest rate going from 2% to 3% is a 1 percentage point increase, but a 50% increase. The distinction matters in finance.
  • Asymmetry of losses. A 50% loss requires a 100% gain to break even. A 33% loss needs a 50% gain. This is why risk management matters more than return-chasing.
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Frequently Asked Questions