I'm currently looking at this Wikipedia article: List of HTTP status codes and it has the following sections that represent HTTP status code classes: 1xx, 2xx, 3xx, 4xx, 5xx.

The same can be found in the Apache documentation (Custom Error Responses):

Although the Apache HTTP Server provides generic error responses in the event of 4xx or 5xx HTTP status codes

As far as I know:

  • four hundred - 400
  • four-hundredth - 400th
  • four-hundredths - 4/100

So the choice to pronounce might be one of the following:

  • four-x-x
  • four hundredth
  • four hundreds

I could not find any dictionary that has an entry for such a "term". I think that some video courses refer to them as "four-x-x" and "four hundredth". I don't remember where I've heard that, but even if I would that won't be credible enough to post here anyway.


Specifically, how to pronounce 1xx and 4xx? I'm asking both of them in case they might differ, because of singular / plural forms.

  • 2
    This question belongs on another site in the Stack Exchange network. Aug 3, 2017 at 22:36
  • @EdwinAshworth There is already a question: How to pronounce “404 Not Found” english.stackexchange.com/questions/62051/… , so I thought that it is appropriate to post my question here. Aug 3, 2017 at 22:39
  • I don't think Computer Science SE existed back then. Aug 3, 2017 at 22:51
  • I suspect you don't understand what "1xx" means. It means all 3-digit codes that begin with "1".
    – Hot Licks
    Aug 4, 2017 at 2:22
  • @HotLicks I am surely understand that 4xx status code includes: 403, 404 and all other codes beginning with "4". I just want to find out / make sure how to read out loud the citation from the Apache docs in my video tutorial. The question is specifically about pronunciation and not the meaning of 1xx / 4xx. Does not seem that this critique is enough for the downvote however... Aug 4, 2017 at 3:47

3 Answers 3


Each of 1xx, 4xx, etc is known as a class of codes. The "4xx" format is a convenient way of writing the class of codes beginning with 4, but four-x-x sounds clumsy if you need to communicate it verbally. I would therefore refer to it as the "four hundred class" of error codes, when speaking.

You could alternatively consider calling that class the "four hundred series" of error codes. This is a familiar usage from product names that use numbers. The vehicles Peugeot 301, Peugeot 302, Peugeot 304, Peugeot 305, Peugeot 306, Peugeot 307, Peugeot 308, and Peugeot 309 are collectively known as the Peugeot three hundred series. The DSLR cameras Nikon D600, Nikon D610, and Nikon D650 are collectively known as the Nikon D600 series. I think it would therefore be clear that you meant errors 400, 401, 402, 403, 404... if you said four hundred series error codes.

  • 1
    Wikipedia indeed refers to them as "classes" and "series": "This class of status code indicates ..." and "... expands the 5xx series of errors", so "four hundred class" and "four hundred series" sounds quite convincing. Speaking "four-x-x" seems to be appropriate only if it is visually visible on the screen. Aug 4, 2017 at 13:48

From personal experience, I would read 1xx as "one-x-x" and 4xx as "four-x-x". Referring to the classes of codes verbally, though, I would usually just refer to them as

  • "hundred (four-hundred) level codes"
  • "codes starting with one (four)"
  • "the hundreds (four-hundreds) codes"

rather than 1xx or 4xx. I think using "xx" in particular is typically used for written specifications.

  • Seems quite reasonable, so +1. But I do not accept it as an answer at least for now. Just in case somebody might come up with other ideas or credible sources. Aug 4, 2017 at 2:11
  • Actually, I suspect that many techies would pronounce them "one-ex-ex", etc. (I know I would.) It's simple and unambiguous.
    – Hot Licks
    Aug 4, 2017 at 11:45

Commonly is spoken with the digits seperated not as a whole... For example 404 page not found, it should be said as "Four naught four, page not found" Another example is 303 rifle. However, the fighter jet, f16 is said as "F sixteen" and so is the machinegun 'M16'

  • 1
    Perhaps you meant 'nought' instead of 'not'. Normally I would read it as 'four oh four'.
    – Hellion
    Aug 4, 2017 at 4:53
  • Yes you're right. Aug 4, 2017 at 5:55

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