"I can't login" or "I can't log in"?

Question

Which is correct:

I can't login?
I can't log in?

I'm confused if that's with a space or no space?

Answer 1

Good question.

There are two words! If you say 'log in' it is generally a verb. On the other hand, if you say 'login' it generally means a noun.

WordWeb describes this -

log in (v) - Enter a computer.
login (noun) - A combination of a user's identification and password used to enter a computer, program, network, etc.

So, in your case, you probably want a verb so it's I cannot log in.

If you want to play with words here, you may say...

"I don't have login credentials (id and password) to log in!"

Answer 2

To test verbs for spaces, try an example in the 3rd person singular. For example:

"He logs in to the computer." (Not "He logins to the computer.".)

To test nouns for spaces, try a plural example. For instance:

"All the logins were invalid." (Not "All the logs in were invalid.".)

Answer 3

Of the two, “I can’t log in.” is the correct choice.

———

Consider the following

I need login credentials, which I will enter into the input fields, in order to log in to the computer.

---

Log in & Login

(to) log in is a verb.

Login can, arguably, only play the role of a noun.

Let's try to conjugate both log in and login as verbs.

    I    | log in   ✔️
   You   | log in   ✔️
(S)He/It | logs in  ✔️

    I    | login   ✔️
   You   | login   ✔️
(S)He/It | logins  ❌

---

In to & Into

In, as is, can play quite a few different grammatical roles. One of these roles, as you can see above, is as a component of the phrasal verb (to) log in.

Into plays a role as a preposition only.

Answer 4

I originally intended this to be a comment, but it was too long, so here goes…

Dropping spaces from phrases to make new words used to be common only to languages like German, not English. However, limitations of some (most) computers in the late 20th Century meant that a generation of people got used to commands that could have no spaces or other special characters in them. The command to "log in" to some types of computer common in the late 70s and 80s was "login" for example, and this restriction has lead to "login" being a common alternate spelling for "log in", at least amongst computer people of a certain age, who are still influential in the tech world.

Ordinary people, who were never, or only lightly, exposed to computers in the late 20th Century, and who don't have to communicate, would almost always use "log in" to talk about what they have to do to identify themselves to a computer system.

IT people, heavily influenced by people who grew up through the computer revolution, or who were part of it themselves, would use "login" to describe the specific technological mechanism, or things related to it. So I'd say "login" was more of an adjective than a noun. "Login" process, "login" program, "login" credentials. The noun usage described on WordWeb, described in @Maulik_V's answer, is then just an abbreviation of login credentials.