I've been working on a 404 page recently and have been confronted with the issue of whether we need to explicitly write the numbers '404' on the 404 page.

My team's opinion on this issue is split. I don't think that the average user knows or cares what 404 means (our average user is fairly non-technical).

Does anyone know of any studies or have a strong opinion about this?

  • 100 Success - Just for completeness.
    – user67695
    Commented Dec 2, 2016 at 17:40
  • 3
    Are you sure the "average user" doesn't know what a 404 is? If they don't, well, now they know. If they do, they know exactly what it means.
    – user69458
    Commented Dec 5, 2016 at 21:09
  • 4
    except success codes are in the 200 range >_> Commented Dec 7, 2016 at 7:27
  • 1
    @FighterJet It would be interesting to see a study, but my feeling is that if you asked any random person what the numbers '404' meant, they wouldn't be able to tell you (generally speaking). If they saw the numbers '404' with a message 'Page not found' in a browser, they may associate the numbers with the message. Will they commit those numbers to memory and associate it with the meaning that what they're looking for doesn't exist? I don't know. But I doubt it. But I guess it's all opinion until someone does a study.
    – Seanevd
    Commented Dec 7, 2016 at 16:32

10 Answers 10


Include the 404 — problem solvers will appreciate it

There’s no better or more concise way to communicate the nature of the problem to experts who may have to help your user.

“404” on your error pages is not harmful

Just to get this out of the way, including the error code is not bad, confusing, or annoying. If it were, major web companies like Google and the UX experts of Nielsen Norman Group, would not still include them.

Will the error code help your support team?

Any error code is meant to convey specific meaning to people who know its meaning.

It is good UX to help your end users get the help they need as quickly as possible. You should make it as easy as possible for your internal users on the support team to provide that support.

If the people who would provide help to your users would benefit from knowing the HTTP error code, then absolutely include it. You want to help your internal users provide the best help to your external users.

But even if your support team doesn’t need the code (for example, if your site throws serial errors that the support team can look up) there are other good reasons you may want to include standard HTTP error codes:

Consider other experts who might help your user

Knowledge of common HTTP error codes is not limited to web professionals. Some of your users will know what a 404 is, and what might help when you encounter one. If they don’t, they may ask someone in their household, office, etc., who does.

Speaking from personal experience, that nearby expert has often been me. I find it highly annoying when a website displays a “too friendly” error page with no useful information. It’s a little better when a site paraphrases the error so that I can wager a guess about what error was thrown. But even when it’s clear this is a 404 page, not seeing the “404” slows me down a little.

Note: Being a web developer, I can find HTTP errors with the browser tools, if the person I am helping seems really desperate. My internet denizen kids, on the other hand, understand 404’s and some other HTTP error codes (or at least have a gut feel about what to do about them) but don’t know how to use browser tools.

Knowing the error code will help a subset of your users. Why withhold these 3 little information-rich digits?


As you say "I don't think the average user knows or cares what 404 signifies" so it doesn't matter to him.

But to the technical user the 404 gives extra information.

So if the decision is between displaying and extra sentence or not, displaying it gives some information to a minority of users, while it doesn't bother the majority (average user).

  • How does "404" give a technical user more information over simply "page not found"? Commented Dec 2, 2016 at 20:38
  • 1
    It gives accuracy that the error is a 404. A "page not found" without a "404" might make the "a little above average" user think it might be a different error; just a guess.
    – Alvaro
    Commented Dec 2, 2016 at 20:53
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    Error 404 is so common that even common user understand it. And for uniformity I guess putting 404 is the best option. Commented Dec 4, 2016 at 5:02
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    Not only technical user, but also someone who knows a technical user.
    – gnasher729
    Commented Dec 5, 2016 at 23:31
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    Both the number and the name can be used. This allows both technical and non technical people to have a chance at distinguishing "404 not found" from "410 gone". Commented Dec 24, 2016 at 1:22

I don't think it is a matter of taste. It's not even so much about displaying the information or not, but rather how to display it. And the answer is that it depends on the website/app: who are your main visitors? Who are your personas?

  1. If one of your Persona represents a person that likes solving problem or has a technical background, than highlight the error type.
  2. If on the contrary, all your Personas don't care or/and don't know about technology, it is not worth highlighting the technical aspect.

In most case, the latter is the privileged scenario (it seems to by your case here). Avoid giving a technical answer to your users. Make it more human, more understandable to them. And if possible, make it even delightful and help them solve the problem by hinting some navigation/topics.

So, IMO, focus on giving a more human answer, and focus on the next step for the user. How do you solve user's problem once they get to this page.


I think it's purely a matter of taste.

404 is a fairly ubiquitous error code. Even many non-technical people have likely experienced the error before. However, to most people the actual number isn't what's important, but the "file not found" error message which is almost always accompanied with it.

As long as you include that message, I don't think whether or not you have the number will particularly matter to the user. If you are giving more information than the user needs, a single 3 digit number isn't particularly distracting or inconveniencing.

There might be a case to be made that a slightly more technical user could use the code to help report a bug to you (confirming that it's a 404 instead of a 403 or any other error code). But that technical user would likely also know that "file not found" means a 404 error anyway.


I think you are in the right path, although it's true that 3 digits are not too distracting the answer is really legit. Where is the necessity?

Hilary Clinton's website

As you can see in the picture they haven't put any number. Anyway you must think if your case does need the 404 or not.

  • 3
    but she lost the elections, so maybe not a good example ;)
    – Devin
    Commented Dec 2, 2016 at 18:58
  • 2
    @Devin Probably the best reason I've seen to display 404. 😂
    – Seanevd
    Commented Dec 2, 2016 at 19:03
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    The example is a very poor "404" page. To a weak English reader it might be incomprehensible. It doesn't say that the indicated page wasn't found. As Seanevd says, good reason to have 404 on it.
    – mgkrebbs
    Commented Dec 2, 2016 at 19:32
  • 1
    I thought the post was worth it for quip @Devin made.
    – Seanevd
    Commented Dec 3, 2016 at 23:00
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    @FedeCrespo, it was a joke :)
    – Devin
    Commented Dec 3, 2016 at 23:10

404 does have the advantage for more experienced web users that it's quick to read. Its almost an 'icon' an so requires little mental processing.

Which means the user has to do 'less thinking' - which users hate doing.

It's two words shorter than:-

"Page Not Found"


The short answer, IMO include it in small somewhere to inform the more technically inclined, but make the focus of your page a clean message telling your visitors that you couldn't find something. An error is distinct and different, you need to communicate clearly that you couldn't find the page.


It is not necessary to include “404” on 404 error pages. It may be helpful, depending on your users.

My first reaction to your question was of course, but then I conducted a survey of the following pages (accessed November 2, 2018 with iOS Safari):

The overwhelming trend is away from including “404 error” on pages (example: Apple 404 error page). Pages that do include the term deemphasized it, focusing the user on a much more noticeable alternative message (example: IDEO 404 error page). I also learned pretty much every short series of characters is a Twitter account!

Avoid ‘Soft 404’ Errors

While it’s okay to leave the words “404 error” off custom error pages, it is important to provide a correct HTTP status code along with the page. A ‘soft 404’ is when a site displays a ‘page not found’ message but provides a ‘200 OK’ status code response. An incorrect status code may trigger nonhuman readers of your website to behave in undesirable ways. Some web browsers may override 404 error pages that are too small. See Custom error pages (Wikipedia).

’404 error’ May Help Your Users

Google, IDEO, and AirBnB are leading companies in web design. Clearly they still think the phrase ‘404 error’ is important for their users. It may be important for your users too. Tim’s answer explains a number of good reasons why.

Custom Error Pages are a Worthwhile Investment

TIME Magazine published 404 Forever: 10 of the Web's Best Error Pages in 2014, so 404 pages are relatively mainstream and can be very important for your brand. A search for ‘best 404 pages’ will return a number of design articles that explore how 404 pages helped define brands, build customer trust, and keep customers smiling, so what ever you decide to include on your page it’s good that your team is taking the time to customize the 404 experience.

Note: osdavison’s comment inspired my search and Wikipedia was the first site I checked.


I would include the literal "404" because some tech support people will incautiously refer to the page by the "404" shorthand rather than "file/page not found".

Plus, as long as the "not found" text is there, including the number code can be slightly educational...and it can't hurt! There's no downside.

If you want to increase the edu value, include, in 12pt type, "for your enjoyment, here's a list of other error codes you might encounter, and their meanings". Many people enjoy having "insider"-type information.


No requirement to include the digits here. Error messages just need to specify the nature of the problem, or they will add to a user's frustration. (Special place in Hell for those "Please try again" pages when Trying Again will not fix it.) As long as you say "file not found" your user will realize they fat-fingered the url or worse, you have link-rot.

At best, a finely crafted custom 404 page can add a touch of delight for your users who somehow found themselves in a dark alley of your internets -- now you have an opportunity to escort them to the safety of pages that actually do exist. I smell opportunity.

Here is a compilation of creative custom 404 error pages your team might enjoy as you discuss how to convey "file not found" without jargon-y numbers, and in a way that fits your brand persona.

  • 1
    #20 will get you one angry non-customer. Quite a few of them I would conclude that the page was created by creative idiots.
    – gnasher729
    Commented Dec 5, 2016 at 23:36
  • #20 looks like an appropriate fit for their brand. I'm not saying it would be appropriate in any other context. Commented Dec 6, 2016 at 16:13

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