Please Note: This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, 2021, and Excel in Microsoft 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here: Converting to Octal.
Written by Allen Wyatt (last updated October 26, 2024)
This tip applies to Excel 2007, 2010, 2013, 2016, 2019, 2021, and Excel in Microsoft 365
There are four types of numbering systems commonly used in programming: binary, octal, decimal, and hexadecimal. Each is simply a different method of expressing the exact same values. Excel makes it easy to convert between decimal and octal numbers and provides two worksheet functions for that very purpose.
The first function is the DEC2OCT function. Suppose you have a decimal value in cell B7, and you want to know how to express that value in octal. In a different cell you could use the following formula:
=DEC2OCT(B7)
If the value in B7 was 456, the result of the above formula would be 710. An interesting fact (and potential "gottcha") is that when the conversion is completed, Excel considers the result to be a number. Thus, if you added 8 to the resulting value above (710), Excel would return 718—a value impossible in octal. This simply means that Excel doesn't keep track of the numbering system used in a particular cell; it expects you to do that.
If you want to convert numbers back the other way, from octal to decimal, you can use the OCT2DEC worksheet function:
=OCT2DEC(B8)
If you try to use this function with a value that is clearly not octal (such as 718), then Excel returns a #NUM! error value.
ExcelTips is your source for cost-effective Microsoft Excel training. This tip (5656) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, 2021, and Excel in Microsoft 365. You can find a version of this tip for the older menu interface of Excel here: Converting to Octal.
Excel Smarts for Beginners! Featuring the friendly and trusted For Dummies style, this popular guide shows beginners how to get up and running with Excel while also helping more experienced users get comfortable with the newest features. Check out Excel 2019 For Dummies today!
Functions are at the heart of Excel's power in working with data. One of the most misunderstood functions provided by ...
Discover MoreThe DSUM function is very handy when you need to calculate a sum based on data that matches criteria you specify. If you ...
Discover MoreIf you need to know the number of columns in a particular range, you can use the COLUMNS worksheet function. This tip ...
Discover MoreFREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."
2024-10-26 10:23:35
JMJ
A famous octal joke: Why is oct 31st the Xmas of geeks? Because 31OCT=25DEC!
Got a version of Excel that uses the ribbon interface (Excel 2007 or later)? This site is for you! If you use an earlier version of Excel, visit our ExcelTips site focusing on the menu interface.
FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."
Copyright © 2026 Sharon Parq Associates, Inc.
Please Note:
This article is written for users of the following Microsoft Excel versions: 2007, 2010, 2013, 2016, 2019, 2021, and Excel in Microsoft 365. If you are using an earlier version (Excel 2003 or earlier), this tip may not work for you. For a version of this tip written specifically for earlier versions of Excel, click here:
Comments