The Short Answer: Is It “Login” or “Log In”?
Use log in when you mean the action of entering an account: “I need to log in.” Use login when you mean a thing, such as a username, an entry point, or the act of accessing an account: “I forgot my login.” The quickest test is to ask whether someone is doing it. If so, leave a space.
That one little space does a surprising amount of work. It can turn an instruction into a label—or make an otherwise polished sentence look as though it lost a word on the way to the page.
The Simple Test: Is Someone Doing Something?
Picture an app asking you to enter your details. What are you about to do? Log in. The two-word form is a verb: it names an action.
Please log in before viewing your messages.
I can’t log in because I forgot my password.
She logged in from her laptop.
Notice that the verb can change tense. You can log in, logged in yesterday, or be logging in right now. In every case, log and in stay separate. Cambridge Dictionary lists log in as a phrasal verb—a verb made from more than one word.
Now compare those sentences with this one:
My login isn’t working.
Here, login isn’t something you’re doing. It’s a thing you have—or, in this case, a thing causing trouble. One word fits.
Try the “doing” question: If the sentence tells someone to perform the action, or says that they performed it, choose log in. If it names the thing involved, choose login.
When “Login” Is One Word
A login can refer to a username or other identifying entry, the act of accessing a system, or an entry point on a screen. That range of meanings can make the word feel slippery, but it has one steady feature: it works as a noun. Cambridge Dictionary records these noun uses, along with the alternative spelling log-in.
I entered the wrong login.
The system recorded my last login.
There’s a login at the top of the page.
You’ll also see login before another noun:
login page
login button
login details
In those phrases, it tells you what kind of page, button, or details you’re talking about. Think of it as a label stuck to the noun. The button may invite you to log in, but the button itself can be a login button. Mozilla’s writing guide makes the same distinction: log in is the verb; login is the noun form used in phrases such as login button.
If the grammar labels aren’t sticking, don’t worry. You don’t need to announce “Aha, an attributive noun!” while trying to finish an email. Just ask whether login names or describes something. If it does, one word is usually the choice.
Put the Two Forms in the Same Sentence
Sometimes the clearest demonstration is to let the words meet:
Use your login to log in.
The first is the thing you use. The second is the action you take. English has handed us a miniature grammar lesson disguised as an IT instruction.
Here are a few more everyday examples:
The login page wouldn’t load, so I couldn’t log in.
After three failed logins, he finally logged in.
Find the login button and log in to your account.
The spelling isn’t determined by where the word appears on the screen. It’s determined by the job it does in your sentence. This is similar to the way a space changes the meaning of everyday and every day: one form describes something, while the other does a different grammatical job.
Why It’s “Log In to,” Not “Login to”
This is the version that makes many writers pause:
Please log in to your account.
Three short words in a row can look odd. Wouldn’t login to or log into be tidier? Not if you want to follow the distinction: log in is the action, and to your account tells us where you’re accessing it. Mozilla’s writing guide recommends log in to the website and advises against log into in instructions.
The same principle appears in other sentences:
I’ll log in to check the schedule.
You must log in to the portal before submitting the form.
In the first example, to check the schedule tells us why you’re logging in. In the second, to the portal tells us where. Either way, in belongs with log, so keep the space before to.
If in to still looks strange, you’re in good company. Our guide to into versus in to explores why two neighboring words sometimes need to stay separate.
What About “Log-in” With a Hyphen?
You may have spotted a third contender: log-in. Is it a typo? Not necessarily. The Chicago Manual of Style accepts log-in or login as a noun, while keeping log in as the verb.
For most general writing, login is a straightforward choice for the noun and for phrases such as login page. If you’re writing for an organization with its own style guide, follow that guide’s preferred spelling. Whatever you choose for the noun, don’t let the hyphen sneak into the verb:
Use: You need to log in again.
Avoid: You need to log-in again.
A hyphen can join words into a label, but it doesn’t replace the space in this action phrase.
What Should a Button Say?
Buttons can be especially confusing because they often contain only one or two words. A button labeled Log In reads as a command: Do this now. A reference to the login button names the button in a sentence.
You might also encounter a button labeled Login. That alone doesn’t change how you should write the verb in ordinary prose. Interfaces use short labels, and different organizations make different wording choices. When you’re writing instructions for a particular app, though, it helps readers if you reproduce the button’s actual label:
Select Login, then enter your username.
That sentence identifies what the reader should select; it doesn’t use login as the verb in your instruction. The action is still select. This is why copying a button label and writing a sentence about logging in are slightly different tasks.
The Pattern Beyond “Login”
Once you’ve spotted the action-versus-thing distinction, a few related expressions become easier to handle. You log out when you finish, for instance; you might then see a logout option. You sign in to an account, even if the site calls its entry screen a sign-in page. Style guides may prefer different labels, so consistency matters when you’re writing for a specific product.
Still, don’t assume every pair of words follows exactly the same spelling pattern. English loves a useful pattern almost as much as it loves an exception. For this particular choice, keep your focus on the sentence in front of you: action or thing?
The One-Line Rule to Remember
You use a login to log in.
That’s the whole test. If someone is doing the action, write log in as two words. If you’re naming the entry, event, page, or button, login is usually one word. The next time a sentence makes you hesitate, look for the job the expression is doing—not just the number of spaces on the screen.