In computer science, you should have a username or a user name or a user-name and a password to be able to log into the system.

Which one is the correct spelling?

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    what about log onto the system? – Preet Sangha Sep 28 '11 at 7:46
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    I believe the correct wording for the logging based alternative would be "log into the system". – bernk Oct 11 '12 at 12:00
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    @bernk Since you can both log into a system and onto a system both would be fine. Most sites have you log in, though some systems use log on since you are using the system (on it) not maintaining or modifying the system (in it). I doubt most people would even notice the difference. Sign vs Log is covered at english.stackexchange.com/questions/2002/logging-in-or-on – Trisped Nov 11 '14 at 23:30
  • Similarly, "file name" vs "filename". – Drew Sep 30 '18 at 3:48

The OED gives ‘username’ and has three citations, from 1971, 1997 and 2007, in support.

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    OED = "Oxford English Dictionary". For those who don't know (I didn't). – Miscreant Jul 13 '16 at 3:25
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    It would be helpful for others if you can provide a link to the same in OED, if possible. IMHO, It would add more value to the answer. – garnet May 21 '19 at 8:53

The correct spelling in this case is username.

  • The username is the (usually unique) thing you type in with your password, for example: bobsmith66.

  • The user name is the name of the user, the user's real life name, for example: Bob Smith. User name is sometimes used for username, but occasionally it makes a difference, so be clear and avoid the ambiguity. (Better still, use full name when you want them to enter Bob Smith.)

  • User-name is a variant of username, but this is rarely used if ever.


Obligatory Google Ngram:

enter image description here

In case the link breaks again: username is much more common these days; user-name is not used at all.

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    This supports the answer I was going to give. "Username" and "User Name" are both relatively common; "user-name" is rare. – KeithS Sep 27 '11 at 18:23
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    I get a completely different graph when I click the link – user107729 Mar 15 '13 at 10:36
  • user-name is used, it is just an order of magnitude smaller than the smallest tick on your graph. – NH. Dec 29 '17 at 23:13

I've seen both "username" and "user name" used widely. Both are acceptable. As far as I know, techies mostly prefer "username". "User-name" just seems awkward.

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    +1. I could have posted an answer, but it would have been essentially the same as this. – Neil Sep 27 '11 at 9:55
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    However I'd argue that user name is the user's birth certificate name in real life, rather than the unique string for logging into the system. – Hugo Sep 27 '11 at 14:18
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    @Hugo, As a software developer, I'd argue that "user's name" or "real name" is their real life name. But software developers sometimes forget who's using the software. – Hand-E-Food Sep 28 '11 at 0:41
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    @Hand-E-Food As a software developer, I agree "user's name" or "real name" is their real life name, but in addition to "user name". I recommend to avoid the ambiguity and stick to "username" for the unique login ID (and perhaps "full name" for the real name). – Hugo Sep 28 '11 at 8:11
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    @Hugo Not quite. The style guidelines exist because the “correct” English word is “username”, not “user name”. In particular, this style guide is regardless of the programming language. The programming language dependent part merely specifies whether you’d write the identifier as userName or UserName or user_name (that is, whether to use camelCase, PascalCase or whats_er_name) but several style guides additionally caution that “username” is a single word and should not be written as either of the above. – Konrad Rudolph Sep 28 '11 at 8:18

Like most things in language, it depends upon context.

If you are writing a journal for a computer science publication, username is acceptable.

If you are writing the user's manual or labeling a field, I would use "user name" since the users may or may not be well versed in computer science, and it just feels less complex.

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    No, as @skst mentioned, the correct general term should be "user id". – Mark Hurd Sep 28 '11 at 12:23
  • @Mark, I have no problem with using "User ID" or "User's identification code" when referring the the user's identification. I am, however, very big on consistency. If the development teams uses "UserName" as a field name and variable name inside the code, reference these elements in technical documents, there is a better than even chance that this phraseology will leak through to the end user. In that case, I'd prefer to use the same term they used so there won't be a document referring to the same item by two terms. – Andrew Neely Sep 28 '11 at 13:53
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    @MarkHurd in UNIX, at least, your username and userid are different. John Smith's username might be "smithj" and his userid be 1043. – slim Feb 2 '12 at 12:10
  • @slim: Yes, I was thinking of Windows where there is a concept of a user's name, a user id and, very much behind the scenes, but most similar to the Unix uid, the user's sid. – Mark Hurd Feb 2 '12 at 15:08
  • Users need not be familiar with computer science to be expected to be familiar with end-user oriented general computer terminology, like "username" or "email" or "password", etc. – jinglesthula Jan 14 at 19:21

In terms of computer science , username is mostly used as a standard. I have always used that.


The O.E.D. often defines words merely because they're commonly used, regardless of their correctness. (For example, I don't consider "LOL" or "ginormous" to be words.)

I realize that it is often used to describe "the thing you type in with your password," but that is more correctly called the user ID since it is not the actual name of the user.

In my opinion, it's a compound noun and the correct spelling is "user name" as in "the name of the user." Just because we can delete the space between two words doesn't mean we should, although plenty of compound nouns do. Language evolves, of course, and it's just as likely that we're in the middle of this word's evolution. In a few years, I may change my mind and edit this entry.

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    You may not consider “LOL” a word but that doesn’t make it less one. Remember, English isn’t a prescriptivist language. Words exist because they are used, not the other way round. – Konrad Rudolph Sep 28 '11 at 8:07
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    You're right that a "username" is more correctly called a "user id", but I believe that "fight" is lost already and "user name" is only the correct spelling of "the name of the user". – Mark Hurd Sep 28 '11 at 12:20
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    I'd also point out that "LOL" is an initialism. Again, not a word. Yes, words exist because they're used, but how much does a construct have to be used before it's deemed a word? And who's the arbiter doing the deeming? These are subjective requirements, and my point was merely that I don't think the O.E.D.'s bar is high enough. – skst Sep 28 '11 at 16:58
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    "I'd also point out that "LOL" is an initialism. Again, not a word. " Is lol a word? Is radar a word? What about scuba and laser? Are acronyms really not words? You are correct that the OED records common usage, not "correctness", because there is no official arbiter of "correct" English. – Hugo Oct 29 '11 at 9:30
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    @skst fwiw, I think people are increasingly saying "lol". Just for the lulz, innit? – slim Feb 2 '12 at 12:11

In computer terminology use the word "username" and/or "filename", always. For variable/class names in computer coding also use "username/Username" and/or "filename/Filename" and never "userName/UserName" and/or "fileName/FileName".

  • -1, for an answer that adds nothing to any of the currently posted answers, and is several months late. – Jay Elston Feb 4 '12 at 1:50
  • My answers that I gave here are the most perfect answers you can get on this subject. Read them again and follow the instructions that I have so lovingly offered to you. – John Feb 4 '12 at 13:31
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    @JayElston: If you don't like an answer, by all means downvote. But what does lateness have to do with anything? Not everyone was a member when a question was asked, and I've seen plenty of questions where a late reply did add value to the discussion – for example, this one. – J.R. Apr 7 '12 at 23:07

From the software-development perspective, username and userName are used the most. Username is used in the user interface and userName with an uppercase N is used in the code.

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    In the code it depends on your language/team's coding conventions, and is irrelevant here. – Hugo Sep 27 '11 at 14:26
