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OCT2DEC Function
Summary
The Excel OCT2DEC function converts an octal (base-8) number to its decimal (base-10) equivalent. It supports both positive and negative numbers using two's-complement notation for signed values.
Syntax
OCT2DEC(number)Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
| number | String/Number |
Yes | Octal number for conversion. Limited to 10 characters (30 bits total). Most significant bit is the sign bit. |
Using the OCT2DEC Function
OCT2DEC is perfect for converting octal representations from programming, embedded systems, or legacy data into familiar decimal format that Excel can easily manipulate and analyze.
Common OCT2DEC Examples
Basic Octal Conversion
=OCT2DEC(54)Converts octal 54 to decimal 44.
Negative Octal Number
=OCT2DEC(7777777533)Converts signed octal 7777777533 to decimal -165 using two's-complement.
Frequently Asked Questions
Common Errors and Solutions
#NUM!
Cause: Invalid octal characters (non 0-7 digits) or more than 10 characters
Solution: Verify input contains only 0-7 digits and ≤10 characters
#VALUE!
Cause: Non-text/number input
Solution: Ensure proper numeric/text format
Notes
- Octal digits must be 0-7 only
- Maximum 10 octal digits (30 bits total)
- Negative values use two's-complement with sign bit
- Common in Unix permissions, embedded systems
Compatibility
Available in: Excel 2007, Excel 2010, Excel 2013, Excel 2016, Excel 2019, Excel 2021, Microsoft 365
Not available in: Excel 2003 and earlier
Content last reviewed: December 9, 2025
Update frequency: As needed
Excel versions tested: Excel 2007+