Percentage Calculator
Two rows sit on the page, each with its own Calculate button: what a percent of a number is, and what percent one number is of another. There is no third mode for percent change.
How to use
- In the first row, What is, type the percent, then the number after of. The sample values are 20 and 150. Click the first Calculate. The math is that percent times the number, divided by 100.
- In the second row, type the part, then the whole after is what percent of. The sample values are 40 and 200. Click the second Calculate.
- Read the line just above the button you clicked. The second result is the first number divided by the second, times 100, followed by a percent sign. If that second number is 0, the line stays a dash.
When it helps
The first row answers a share of a total, such as 15 percent of 80. The second row answers the reverse, such as 12 out of 80. Each result shows at most four decimal places, so a repeating fraction is shortened instead of running on.
This is arithmetic on the numbers you type. It does not look up a tax rate or a grading curve. For a price plus a rate, use the Sales Tax Calculator, which has Amount and Tax rate. For scores entered as a percent and a weight, use the Grade Calculator.
Limits
There is no percent-change third mode. You cannot enter an old price and a new price and receive an increase. You can subtract yourself, then put the difference and the old number in the second row. The page will not do that subtraction, and it will not label the result as a rise or a drop.
The second number on the second row cannot be 0, because that row divides. A blank second box is read as 0, so the result stays a dash. The first row may use 0. Negative numbers are allowed and are not described as discounts.
Questions
Which Calculate button belongs to which row?
The first Calculate sits under What is, percent, of, number. The second Calculate sits under part is what percent of whole. They do not share one result line.
Why does the second result stay a dash?
The second number is 0 or blank. Division by zero is refused. Type a non-zero whole and click the second Calculate again.
Can I get the change from 80 to 100?
Not as its own mode. The difference is 20. Put 20 and 80 in the second row to see what percent 20 is of 80. The page does not call that an increase for you.