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Percentage Calculator
Calculate percentages, find what percentage one number is of another, and compute percentage change.
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
Choose Your Mode
Select from three percentage calculation types.
Enter Your Values
Type in the numbers you want to calculate.
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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