Should the unit "Ohm" be capitalized or not? For example, "kOhm" versus "kohm" vs "kΩ", which is most correct?

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    \$\begingroup\$ I would say it is matter of preference. IMO: kΩ > kOhm > kohm \$\endgroup\$ – d3L Dec 31 '15 at 7:51
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    \$\begingroup\$ SI standard says use lower case for units named after somebody when written out long form and capitalise the first letter for the symbol. V for volt, A for ampere, Hz for hertz, Ω for ohm, etc. \$\endgroup\$ – Transistor Dec 31 '15 at 10:22
  • \$\begingroup\$ @transistor right, but kohm looks like a hybrid: long "ohm", but contracted "kilo". \$\endgroup\$ – Ruslan Dec 31 '15 at 12:51

In my experience "kΩ" is preferred, but if you don't have the "Ω" symbol available on your computer then you need to write out the full words in lowercase: "kilo ohm".

See here for the standards on writing out SI units: https://en.wikipedia.org/wiki/International_System_of_Units#Writing_unit_symbols_and_the_values_of_quantities

Edit: The Wikipedia article on the ohm says it should be "kilohm" if written out, which I've not seen in my experience, but I'll include this for full reference.


  • \$\begingroup\$ Just going to add this here to justify the need to write out the word if the symbol is lacking poynton.com/notes/units "Write a numeric value with units in either the journalistic style, using prefix and unit names (four kilohertz); or the scientific style, using prefix and unit symbols (4 kHz). Don't mix these styles: Do not mix a prefix name with a unit symbol (WRONG: kiloHz), or a prefix symbol with a unit name (WRONG: kHertz). Avoid "abbreviations" for units (WRONG: sec., amp); use the unit names or symbols instead. " \$\endgroup\$ – Dave Dec 31 '15 at 8:30
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    \$\begingroup\$ @Chu, That's the Symbol. ampere = A, volts = V, ohms = Ω (this is a capital Omega), coulomb = C, hertz = Hz, etc. NOT THE NAME, which is always written lowercase. All of these have capitals for their SYMBOLS unlike say meter = m, second = s, gram = g, etc. \$\endgroup\$ – Dave Dec 31 '15 at 8:50
  • \$\begingroup\$ @Dave, yes that's correct, I'll delete my original comment. \$\endgroup\$ – Chu Dec 31 '15 at 9:03

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