How to Use Negative Numbers to Calculate in Excel

Microsoft Excel spreadsheets can handle inventory: what you have, what you had, what you sold and what you have left. You can input figures into a Microsoft Excel spreadsheet and subtract a number from what you originally had in inventory to determine what's left. You can use negative numbers to show the difference; for example with "15 - 10," this equation is actually "15 + (-10)."

You can format the way negative numbers appear in your spreadsheet. Numbers can be formatted with a negative sign, with double parentheses, or by using the colour red.

Enter a negative number into an Excel spreadsheet cell by using the minus sign (-) before the number.

"-12" is an example of a negative number.

Use the arithmetic operator, the minus sign (-), to subtract a number using a formula.

An example is the formula, "=25-10" that will give a result of "15."

Use a function to calculate negative and positive numbers.

An example of this is "=sum(a1:a3)", where cell a1=10, cell a2=12 and cell a3=-25 will give a result of "-3."

Use a function to transform a positive result into a negative result by applying the negative sign (-) to the function. An example of this is "=-sum(a1:a3)" using the established values for those cells will give a result of "3."

Select a number or range of numbers to change the way Excel displays these numbers.

Click the "Home" tab on the top menu and select the arrow in the "Number" section.

Choose either the "Number" or the "Currency" category in the "Category:" list in the "Format Cells" window.

Select the number of decimal places by either typing it in or selecting the up or down arrow in the "Format Cells" window.

Choose the "Use 1000 Separator (,)" check box. Skip this if you are formatting currency.

Choose the currency symbol by clicking the down arrow in the box next to "Symbol." Skip this if you are not formatting currency.

Select the number format in the "Negative numbers:" box in the "Format Cells" window.

Click the "OK" button.


Negative times will be displayed as number symbols (####). You can adjust the way the number is displayed by using the TEXT function.

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About the Author

Based in New York, Kate Bluest has been writing for various online publications since 2005. She has participated in several writing workshops, including the MIT Writing Workshop. Bluest holds a Bachelor of Science in business administration from SUNY Empire State College.