Off symbol ( O )
Off. A circle on a switch marks the off position: IEC 60417-5008, “off” (power).
Easily confused with
How to read it
The circle is IEC 60417-5008. The IEC defines it to indicate disconnection from the mains, at least for mains switches or their positions, and in all cases where safety is involved. It is the partner of the line for on, and the draft of IEEE 1621 in Lawrence Berkeley National Laboratory’s 2002 report says it is best used with the on symbol, as on a rocker switch. The 2014 Unicode proposal typed it as a zero, “binary zero”. Unicode did not add a separate character for it: its chart notes that the heavy circle, U+2B58, is used for the power off symbol.
Also searched as: circle symbol, off symbol.
Look-alikes
A circle with a line inside it is the Power on/off symbol symbol, and a circle broken at the top with a line in the gap is the Power symbol.
More power and device symbols
Sources
- ISO/IEC/JTC1 Graphical Symbols for Office Equipment, Table of IEC 60417, ISO 7000 and ISO/IEC 13251 power symbols, Lawrence Berkeley National Laboratory (Internet Archive copy), IEC 5008
- The Power Control User Interface Standard, Consultant report P500-03-012F (Alan K. Meier and Bruce Nordman), December 2002, Lawrence Berkeley National Laboratory for the California Energy Commission (Internet Archive copy), Attachment I, Table 1
- Proposal to Include IEC Power Symbols, Unicode document L2/14-009 (Terence Eden, Joe Loughry and Bruce Nordman), 23 January 2014, Unicode Consortium document register, table 6
- Miscellaneous Technical, Range: 2300–23FF (code chart), The Unicode Standard, Unicode Consortium, U+23FD
- Miscellaneous Symbols and Arrows, Range: 2B00–2BFF (code chart), The Unicode Standard, Unicode Consortium, U+2B58
Last reviewed September 26, 2026 by Rory Hansen. How we research