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How to Write a SUM Function in Excel

Jason Morrell

by Jason Morrell 
March 13, 2023

The SUM function in Excel is the first one you learn. That's because one of the most common things you need to do in Excel is calculate a total.

In this post, you'll discover different ways to create a SUM function and different examples you can dissect.

1.  Example 1: How to write a basic SUM function in Excel

Consider this simple data:

Excel base data

To calculate the total of these numbers using a SUM function:

1.  Type =SUM(

2.  Select cells A1:A5 with the mouse (you can type the cell range but then you may get human error)

3.  Type the closing bracket and press Enter.

A basic SUM function in Excel

This calculates the total, 100.

The total using the SUM function in Excel

2. Anatomy of a SUM function

  • Every formula starts with '='. 
  • SUM tells Excel what to do, i.e. add up these numbers.
  • The cells or cell ranges inside the brackets tell Excel what to add up.

Here are some examples:

=SUM(A1:A5, C1:C5)

3. Example 2: How to generate SUM using AutoSum

The AutoSUM button is the beginner's best friend. You'll find it on the Home ribbon.

1.  Select the range of cells you wish to add up, or select the blank total cell.

2.  Click the AutoSUM button (you can also click the AutoSUM dropdown arrow then choose SUM but that's an extra click!)

Choosing SUM from the AutoSUM button

3.  Excel writes the SUM function for you. Press Enter to lock it in.

4. Example 3: How to SUM up summed data in Excel

If you already have data that has been summed, you can add up these values too. In the example below, every 3 months the quarterly column has been created to total the data. Columns D and H contain SUM functions for each row. 

To total up all the quarterly data, the SUM function refers to the cell ranges D2:D6 and H2:H6.

The SUM function to calculate the half-yearly grand total

5. What next?

I hope you found plenty of value in this post. I'd love to hear your biggest takeaway in the comments below together with any questions you may have.

Have a fantastic day.

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About Jason Morrell

About the author

Jason Morrell

Jason Morrell is a professional trainer, consultant and course creator who lives on the glorious Gold Coast in Queensland, Australia.

He helps people of all levels unleash and leverage the power contained within Microsoft Office by delivering training, troubleshooting services and taking on client projects. He loves to simplify tricky concepts and provide helpful, proven, actionable advice that can be implemented for quick results.

Purely for amusement he sometimes talks about himself in the third person.


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