Add recurring charges to see your monthly equivalent, annual spending and long-term total.
Percentage Calculator
Find a percentage, calculate a change or discount, or express a part as a percentage of a total.
How to use it
- Choose the calculation: percentage of, change, discount or part of total.
- Enter the two numbers using the labels shown for that calculation.
- Calculate and read the formula. Editing the inputs clears the earlier result.
Examples
A discount and a price change
- Input
- 20% of 150; 20% off 150; change from 80 to 100
- Result
- 30; final price 120 with saving 30; relative increase 25%.
Four percentage formulas
Percentage of a value is percent ÷ 100 × value. A part as a percentage of a total is part ÷ total × 100. A discount subtracts price × discount ÷ 100 from the original price.
Percentage change is (new − old) ÷ |old| × 100. The absolute denominator makes increases from a negative starting value positive. A zero starting value or total cannot define a relative percentage.
Precision and interpretation
The display rounds to at most six decimal places; calculation uses JavaScript floating-point numbers. This is a general arithmetic tool, not a currency or accounting rounding system.
A change in a percentage is different from a percentage-point change: from 20% to 25% is five percentage points and a 25% relative increase.
Questions, answered.
What if the starting value is zero?
Relative percentage change is undefined, so enter a nonzero starting value or compare the absolute difference.
Can numbers be negative?
Yes, except a discount requires a nonnegative original price and a discount from 0% to 100%.
Are my figures uploaded?
No. The calculation and optional text exports happen in the browser.
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