Is there any serious difference between logoff, logout, signoff and signout?

Websites seem to use the phrases interchangeably. Is this just a difference is style, or have they made a deliberate choice?

  • 2
    Referential ELU post.
    – Mistu4u
    Commented Feb 11, 2013 at 6:41
  • Is your question restricted to how these terms are used online?
    – user230
    Commented Feb 14, 2013 at 11:06

2 Answers 2


In the past when there were no computers, in office or in any secured place, people sign in by signing their signature and time in while entering into the place. When they leave, they sign out by putting the time out and sign. Website followed these words (sign-in and sign-out) in the similar way when computers came.

The notebook that people sign in and sign out basically contains logs, so it's called logbook. So it's also valid to use "login and logout" instead of "sign in and sign out". But in those days, "login" and "logout" was not used much mainly because of the fact that you are signing; signing is the most important event there.

When computers came in 1980s, the security is the most important thing, so most of the operation that user do are logged in the system. There are error logs, security logs, transaction logs and many more.

So when a user is allowed into a secured website by taking the username and password, this event is also logged in the system for security reasons. So technically speaking, it's meaningful, valid and better to call this events as "login and logout" instead of "signin and out" because you don't actually sign. But many still use "sign in and sign out" as well just following the old days. But you can see here, the use of "login" peaked after 1990. Logoff is just a synonym of logout.

  • 3
    It's valid to use "log in" and "log out" as alternatives to "sign in" and "sign out". These are phrasal verbs. Same applies to "log on", "log off", shut down". However, it's valid to use "login" and "logout" as alternatives to "sign-in" and "sign-out". These are nouns. Commented Mar 3, 2015 at 10:36
  • Good Answer. Other examples of "Real world" inspired IT terminology include Data store, Classes and Objects, Bug (a harmful micro-organism becomes harmful piece of code), Memory, Process, Array, Queue, Stack and Semaphore (used in multi-tasking) Commented Mar 3, 2015 at 22:23
  • You do "sign" when you sign into a computer system. Just not with a pen on paper! Your password is your signature.
    – Samir
    Commented Aug 22, 2022 at 12:52

Logoff and Logout are synonymous meaning "an act of logging out of a computer system."

Whereas Signoff is a phrasal verb having following meanings:

  1. To announce the end of a communication; conclude.

  2. To stop transmission after identifying the broadcasting station.

  3. Informal To express approval formally or conclusively: got the Congress to sign off on the tax proposal.

Sign out means:

To record the departure of another or oneself by signing a register.

So "logoff" and "logout" mean the exact thing when we log out of a computer system or web. "Sign off" or "sign out" is also same in terms of the specific meaning of end of communication by signing. When we logout, a log is registered with several information in the websites to keep track of a user. So all of them are correct in terms of usage in websites.

  • 14
    Actually signoff is not a phrasal verb unless you're allowing it to be misspelled. As a verb it should be spelled sign off. The same goes for the other alternatives. The spellings written as a single word are nouns, those with spaces are verbs, and those with hyphens are adjectives. It is getting more and more common to write them as single-word verbs but I wouldn't say it's accepted. One problem with it is that it would make them irregular verbs, defective verbs, or lead to inflected forms such as I signoffed. Commented Feb 12, 2013 at 0:49
  • 2
    Right on, bro—one of my major pet peeves! Commented Mar 3, 2015 at 10:43

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