How to Subtract 20% on a Calculator

How to Subtract 20% on a Calculator
••• Liderina/iStock/GettyImages

Learning to do basic math in your head is useful, but there are times when you need to make sure you are calculating the problem exactly. To subtract any percentage from a number, simply multiply that number by the percentage you want to remain. In other words, multiply by 100 percent minus the percentage you want to subtract, in decimal form. To subtract 20 percent, multiply by 80 percent (0.8). To subtract 30 percent, multiply the number by 70 percent (0.7).

Before beginning, determine the gross amount you want to use before subtracting a percentage. On many bills or estimates, you may prefer the gross total before taxes have been applied. Subtracting 20 percent off a number that has additional taxes and fees might skew your overall estimate.

Using a Calculator

1. Enter the amount from which you want to subtract 20 percent on your calculator. As an example, assume the total is $85.50.

2 Press the multiplication button – × – on the calculator..

3. Enter “0.8” to represent 80 percent, then hit the equals button. In the example, $85.50 × 0.8 = $68.40.

Related Articles

How to Divide Square Feet
How to Figure Discount Percentages
How to Increase a Number by a Percentage
How to Calculate Percent Off
How to Add Percentage to a Price
How to Calculate a 10 Percent Discount
How do I Calculate 0.1%?
How to Use a Calculator to Figure Percentage
How to Figure Discount Percentages
How to Calculate the Top 20 Percent
How to Find Out How Much 6% Is of a Number
How to Find the Answer to 20% of What Number Is 8?
How to Calculate the Percent of One Hour
How to Convert From Moles Per Liter to Percentage
How to Calculate Fractions to Percentages
How to Convert Grams to Ounces for Gold & Silver
How to Calculate the Percent of Something
How to Use the Percentage Key on a Calculator
How to Calculate Percent Difference With Three Sums