← Back to context

Comment by ctxc

2 days ago

TIL GSM is just g/sq m. Like duh, feel so stupid xD

It's not you who should feel stupid.

The person deciding to use nonstandard "GSM" as a unit instead of the proper "g/m²" needs to feel stupid...

  • I'm not sure I agree. "GSM" is three syllables, versus four for "grammes per square metre". You can write it correctly using only characters everyone knows how to type quickly on their keyboard, versus either finding a way to get that superscript ² or else typing something like g/m^2 which is uglier and longer. And you can use it comfortably even if you are a complete mathematical ignoramus (you just need to know things like "larger numbers mean heavier paper" and "cheap printer paper is about 80gsm" and so forth) without the risk of turning g/m² into the nonsensical g/m2 or something.

    (But arguably what whoever decided on "gsm" should have done was to just use "g", with the "per square metre" left implicit.)

    • Roughly no one already says GSM. When talking about paper you'll hear people say things like "That's a sheet of 120 gram"

      GSM basically only ever appears in print. If someone DOES ask "what does 120 gram mean here?" the clarification is going to be "Oh that's grams per square meter" and not "Oh that's gee es em"

      I should mention GSM is also probably an americanism. I'm in the EU and out of the five packs of different kinds of art paper four are labeled in g/m2, and one has no labeled weight at all. None of them are marked in GSM as that abbreviation only works in english, while g/m2 works in all languages.

      2 replies →

    • I beg to differ. You can totally get away with g/m2 which is not hard to type and crucially has a / to hint you what it could be about

      "gsm", or even more so "GSM", belongs to the reign of abbrevations and put my brain on the wrong track

  • "The person deciding to use nonstandard "GSM" as a unit instead of the proper "g/m²" needs to feel stupid..." ---> This is the sort of HN comment that I can't figure out if it's serious or a joke. I can read it in different voices and come to opposite conclusions haha

    • While we're at it, mph and the abomination that is "kph" (= km/h) even more so need to die in a fire.

  • Ummm, not really, No.

    The shorthand "gsm" is a completely standard alternative in some industries.

    I work in advanced composites. Different weights and weaves of technical fabrics such as carbon fiber, kevlar, fiberglass, etc. are always specified in "gsm". For example, some common fabrics would be a "Carbon Fiber 3K 200gsm Twill" or a "High Modulus 12K 380gsm Carbon Fiber Plain Weave". (the "3K" and "12K" refer to the number of carbon fiber strands in each yarn in the weave, and the "Twill" and "Plain Weave" refer to the pattern in which the yarns are woven into a fabric.)

    I'm sure "gsm" came to be commonly used instead of the more scientific "g/m²" or "g/m^2" because no one is doing that kind of math about the materials, and it is a lot easier to type "gsm" vs either of the other two which require at least a Shift for the caret or getting out the superscript font attribute.

    • Interestingly, sail cloth (for sail boat sails) is measured in ounces per square yard, and is just referred to by the weight with the square yard assumed - like "8oz Nylon mainsail" or "4oz ripstop spinnaker". (Or at least it used to be, my expertise here is more than 30 years out of date now.)