The Ultimate Guide to Sign In, Log In and Similar

One of the UX and Technical Writing nightmares is when you try to come up with or unify the way to let your customers “get into” your product. Sign in, sign out, log in, log out but also sign up, register, join, create an account. And what about nouns of those verbs? Login and sign-in? Which one is the right one? Let’s unite the world.

Tomas Nosek
10 min readFeb 18, 2020


A lot of terms, processes, and approaches in the world of the Internet are specified and given. However, when it comes to the activity of getting into or out of a product, the authorities are silent. When checking the dictionaries, most definitions say the same thing only with different words.

For example, the Cambridge Dictionary says that one of them is used “to connect to a computer system by putting in a particular set of letters or numbers” while we use the other “to enter your personal details into a website, etc. so that you can use it.” That’s actually how I thought it’s used — log in for operating systems and sign in for the online world.

screen — illustration purposes only.

It’s not that simple, though. To narrow down the research a bit, I’ll be focusing on SaaS products only. Even though I tried to be thorough in all directions and haven’t found significant differences, there might be some nuances, so I’m disclosing in advance that the primary outcome is going to be about the Internet and its online products.

TL;DR: Don’t have time? I can reveal that the world is divided between two variants — log in, log out, sign up (with login, logout, signup) and sign in, sign out, create account (with sign-in, sign-out, nothing specified for account creation).

So What is the Fuzz About?

There are two main reasons why all this logging and signing is a problem.

Firstly, you want your users to be able to get into your product as smoothly as possible. I guess I don’t have to list all the reasons why it’s good for the users to get into their accounts. In general, the less friction, the higher the probability that your users will get hooked in and use your product. They can also benefit from better personalization while you, as the creator, can get better user statistics.

Secondly, it’s one of the things that almost everybody tends to have an opinion on, even though they don’t work with language, writing, or user experience at all. As nearly everyone thinks they can write documentation or create UI designs, everyone thinks they are the ones to decide. And for the rest, it’s that obvious that they just write there something and don’t validate further.

At Kentico, over ten years ago, different terms were introduced in different parts of the company. One set of the terms was on the website, a different one was used within the software (an on-premise CMS). We managed to unify it later, at least in some places. Yet, when we created a new product, Kentico Kontent, a SaaS CMS, a similar thing happened again. While we took care of the naming in the product — sign in, sign out, and join were everywhere — and gave ourselves a pat on the back, we later changed the service behind it, /login was put in the URL, and we didn’t manage to change it before the release.

But the opinion is divided, so the goal of this article is to show which set of terms is the most used, which should create a guideline for the future.

Style Guides of the World, Unite!

The first phase of the research was to check what different style guides have to say about this. I chose four well-known style guides.


At Kentico, our internal style guide for Technical Writers goes out from Microsoft and their Microsoft Writing Style Guide, previously called Microsoft Manual of Style, when it still was a printed book. In their current online edition, they unanimously claim sign in and sign out are the correct choices in all situations.

In the book version from 2012, though, Microsoft used to recommend log in and log out for getting into a computer or a workstation. Based on this, we can say that it’s evolution and log in/out slowly transforms into sign in/out.

Another interesting fact is that it says explicitly to avoid noun and adjective forms. I guess sign-in page is just too ugly to look at for Microsoft.

Unfortunately, the style guide doesn’t say anything about signing up or registering (already acknowledged by MS), and it also doesn’t tell us if we should use sign in to or simpler but sometimes frowned-upon sign into.

Recommendation sum-up: sign in, sign out, no nouns


Google has their Developer Documentation Style Guide, which also describes this term problem. We can see a similar stance to Microsoft. The difference is that they are completely okay with sign-in for nouns and adjectives, and they also note specifically that you always sign in to, not into.

Unfortunately, the style guide again omits the process of registration.

Recommendation sum-up: sign in, sign-in, sign in to, sign out, sign-out


Mailchimp has one of the most-known style guides. I guess their Content Style Guide was one of the first style guides made publicly available online as something to be proud of.

Not being very talkative about this topic, they just recommend using log in and login for getting in the app, and sign up with signup for the process of registration.

Unfortunately, it doesn’t say anything about log in to vs. log into, which is also a pretty common variant, definitely less frowned-upon than sign into.

Recommendation sum-up: log in, login, sign up, signup


If we reach into open information, the first service in mind will probably be Wikipedia Manual of Style.

Though pretty detailed regarding whether to use log on, log in, or sign in, it’s not very descriptive of the other actions. I haven’t found anything about them.

For accessing accounts over the Internet, the recommendation is using sign in with a separate to when needed. For computers and workstations, they recommend log in.

Recommendation sum-up: sign in (to)

Style Guide Results

Well, in general, the favored variant is sign in with to separated when needed and sign out. However, the results weren’t unanimous, and given the fact I checked four of them only, I wouldn’t consider them having the definite answer.

If you want to see the specific quotations from the style guides and links to them, check this page.

Reality For the Rescue!

Even if all the style guides said one thing, the question would still be how the terms are really used on the Internet. I decided to check some web products, and by the end of writing down the services, I had 25 of them on the list. Besides the terms themselves, I was also checking the URL path of the actions and noted down any differences.

In the product mix, I included larger brands like Google or Microsoft, cool brands like Netflix or Spotify, brands working on work software like Atlassian or Slack, and I also added a couple of rather fun brands like 9gag and AliExpress. In the end, however, this division (or any I came up with) was inconclusive regarding the results.

Getting In and Out (aka Logging In and Out)

When talking about getting in the product and out of it, it’s halfsies between sign in/out and log in/out. So even though I didn’t get THE answer, I got at least some observations:

  • In to is usually preferred to into regardless of the term being log in/out or sign in/out.
  • Brands don’t have it unified on their websites themselves.
  • Sign-in for nouns and adjectives is used in general, though some companies don’t use it or use it for verbs as well.
  • The URL paths often mismatch the actually used term. Who knows why that happens, I guess it’s either due to historical reasons or better keywords for search engines.
  • No one really uses log on/off or sign on/off.

Getting Inside (aka Registering)

The process of registering, signing up, and similar doesn’t seem to have any rules whatsoever. It’s a street fight — anything’s allowed. The few things gathered are:

  • The most used is sign up and create account, which is usually described differently on every website. Sometimes it’s just create account, sometimes it’s create a new account, and sometimes it’s create <brand> account. With that all, sign up and create account were just around two-thirds of the product mix.
  • The most used URL path is /signup, around half of the products used it.
  • If you use log in and log out, you’ll probably end up using sign up. And vice versa, those who use sign up never use sign in and sign out. Having two buttons next to each other that are labeled similarly is not the best practice, I guess.

Reality Results

It turns out that a good rule of thumb is to use either sign in and sign out with a verb for registration, which will typically be either create account or join or log in and log out with sign up for registration.

Regarding verbs, nouns, and adjectives, just go with your gut as all the companies use it just randomly. It’s similar to capitalization, some use it as a name, so Sign In or Log In, while others tend to treat it as a normal sentence.

If you want to see all the data from the checked products, check this page.

What’s Internet Got to Do With It?

I tried to find research or publications about this issue on Google. However, only a couple of articles or forum posts came up.

In general, their recommendations go against each other. I find the opinion of Anthony from the UX Movement to be the most valuable. He claims that it doesn’t matter which combination you’re going to use as long as you use visually different variants for getting into the system and getting inside the system so that they don’t look similar. That’s because those two buttons are always close together, usually on some kind of homepage.

So ideally, don’t use two terms that both contain sign or both contain a preposition (even though a different one). For example, bad ones would be sign in, sign out, and sign up or log in, log out, and sign up.

Google Ngram

Then, I tried to compare Google’s Ngram Viewer results. If you don’t know it, the Ngram Viewer is a tool that compares strings in books. I checked the English corpus from the year 2012, which was the newest one at the time of writing. The results are, therefore, a bit outdated, but still, let’s check them out.

In books, it turned out that sign in has been used pretty much forever while log in and log on boosted with the rise of computers. The most exciting finding was that even though log on peeked even more in the 80s, it then quickly dropped to the log in level. Among nouns and adjectives, sign-in hasn’t been used at all while log in dominates. Finally, all three — sign out, log out, and log off — emerged between the 1960s and 1980s. Again, log off peaked even higher than log out. However, both later dropped, and all three are used similarly.

I think it makes sense even instinctively as I can remember website in the 2000s using log on, yet I don’t know any website now that would still use that.


Understandably, you might oppose that comparing books (especially older ones) when looking into SaaS products is useless. That’s why I decided to compare the world of the Internet too. Using a Googlefight, I compared the same terms.

In the Google battle, I could see that log in is used more often. On the other hand, that might be only because the data for sign-in is more inconclusive as Google cannot differentiate terms with and without hyphens. For registering, though, sign up was far the most used term.

Internet Results

Even though we have some winners here, I don’t think they were conclusive and relevant enough to take it really into account. If we did, log in, log out, and sign up were the top terms used.

If you want to see all the checked sources, check this page.

All That Matters Is the Results

If you kept reading until now, you’ve already seen that the results are at least a bit messy. However, you can see a pattern evolving. When looking deeper, two main branches have emerged that have some edge-case differences.

The first pattern is to use the log in, log out, and sign up trio for verbs while using login, logout, and signup as nouns and adjectives. Going deeper also into the usage of English, I can recommend using log in to separately, but using into is not a serious offense. I would guess that this pattern is used the most in general.

On the other hand, the second pattern is to use sign in, sign out, and create account in some form as verbs while using sign-in and sign-out for nouns and adjectives. Regarding that “some form” of create account, it’s mostly used as create <brand> account, but the actual usage varies. Similarly, regarding nouns and adjectives, go with your opinion there. This pattern, I would guess, is the most used among the “big players”.

What you shouldn’t use as it’s definitely killed-off is log on and log off. It’s just too 2000s… Register is also slowly disappearing from the world of the Internet. The term for registering is complicated even more, though, because it relates to product adoption and activating users of the product, so it then doesn’t depend only on the correctness of its usage, but marketing heavily joins the discussion.



Tomas Nosek

Customer Education and Consulting team leader, occasional blogger, a movie person, comfortable traveler. Find all my articles at