How to Use the Percent Key on a Calculator

The percent key is a time saver.

A percentage is a decimal expression of some portion of a whole. Generally, when we write the term, we do so as 45 percent, or 10 percent. Mathematically, this means 0.45 or 0.10, some number less than 1. So to translate a percent as a whole number to its mathematical equivalent, you need to move the decimal point over two places, from 45 to 0.45, for example, and this is what the percent key on the calculator does automatically. This gives you a quick way to figure out the percentage of any given number, without having to enter decimals.

Instructions

1. Enter the number for which you want to calculate a percentage, for instance 500, on the calculator.

2. Press the multiply key ("X").

3. Enter the percentage you want to calculate for, say 25.

4. Press the percentage key ("%"), and your answer, 125, will appear, showing you that 25 percent of 500 is 125.

References

• The Straight Dope: How Does a Calculator Percent Key Work