Just when I generated a GUID, I found some hyphens in between the character and also at specified intervals


Is there any story behind this?

Note: My intention is to remove those hyphens as I am adding this GUID to a filename and our filename should only be aplhanumeric.

  • 1
    I think it's for readability. Although I must say it's a very strange placement of hyphens if that's the reason for them...
    – gablin
    Commented Dec 25, 2010 at 22:54
  • A GUID has several fields
    – JoelFan
    Commented Feb 26, 2015 at 22:15
  • See more stackoverflow.com/a/24484051 and stackoverflow.com/a/786541, which I found after asking myself a similarly worded question to the OP. Though apparently not technically valid per the spec without the hyphens, it appears to have no legitimate functional purpose for the UUID itself. See RFC4122 for lots of detail. Commented Dec 21, 2020 at 14:12

2 Answers 2


The hyphens are always placed at the same position, so you won't lose any information (or unique-ness) by removing them.

See Stack Overflow: Why are there dashes in a .NET GUID? for a detailed explanation.


Long sequences are very hard to parse for humans, hence the hyphens. But GUID itself is just a number, so you can drop them.

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