RFC 2606 standard reserves the domain names example.org, example.net and example.com for the purpose of being used as examples in documentation.

What is an equivalent for a phone number (including country code) that can be used as an example, e.g. for giving users an example in what format to input phone numbers?

In the best case, it would be a dummy number designated by the relevant standards to be an example phone number, and which would not be attributed to any real subscriber.

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    An interesting question, considering that software documentation and online help often present exemples, and that nowadays, nobody would like to accidentally provide a real telephone number and get sued because GDPR might consider it as disclosure of personal data ! – Christophe Aug 7 at 17:32
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    Do you need to have actual numbers or would illustrating the format with placeholders (e.g., +230 5 nnn nnnn) work? – Blrfl Aug 7 at 18:22
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    This might be better suited for the UX stack – mmathis Aug 7 at 19:34
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    I'm voting to close this question as off-topic because this has nothing to do with software engineering – esoterik Aug 7 at 20:55
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    867-5309! Oh, you need an area code, too? – palswim Aug 8 at 5:03
up vote 136 down vote accepted

The North American Numbering Plan reserves 555-01 numbers for fictitious purposes. If you want an example Seattle number, for example, +1 206 555 0100 - +1 206 555 0199 would do.

In the United Kingdom, Ofcom, the regulator, has set aside numbers for this purpose. For example, if you want a Leeds number, +44 113 496 0000 - +44 113 496 0999 may be used.

I'm sure other countries will have similar things, but I doubt there's one consistent rule across all countries.

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    Interesting ! Here are some more countries: en.m.wikipedia.org/wiki/Fictitious_telephone_number . In addition, it seems that international prefixes +0 and +999 are reserved, so that numbers starting with these prefixes should in principle be fictitious as well. – Christophe Aug 7 at 18:05
  • What a pity that the wtng and which gives a lot of useful information per country code doesn't also provide this kind of details ! – Christophe Aug 7 at 18:14
  • 0 is used by the phone company. +0 followed by a number traditionally meant ask the human telephone operator to assist you in calling that number. For example, you could request the long-distance charges be accepted by the call's receiver, and they pay the bill for the call. – Alan Baljeu Aug 16 at 18:49

An oft-used example phone number is the numeric progression.

(123) 456-7890

It's widely understood that this doesn't mean you should call that number -- it's an example. Additionally, according to the North American Numbering Plan, it's an invalid number -- area codes can't start with 1.

Alternatively, if you don't need digits, the pound sign, all zeroes, or some other pattern could be used as well.

(###) ###-####

(000) 000-0000

(Note that triple 0 is the Australian emergency number, so use all 0's with caution. Thanks @Gary for the heads up.)


If you actually need something that's designated by regulatory standards: Wikipedia: Fictitious Telephone Number has numbers designated by country. For example, in the US, 555 numbers are almost universally fake, although only the 555-01xx series are officially reserved, according to Wikipedia. The UK's Office of Communications has added many numbers to a list (e.g. 0306 999 0xxx) as well, in addition to many other countries.

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    Under the current North American Numbering Plan, the example number you give is an invalid number: area codes can't begin with a "1". Unlike the reserved numbers (the 555-01xx series), this is subject to change in the future. – Mark Aug 7 at 20:31
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    Triple 0 is the emergency phone number for Australia (equivalent to 911 in US or 999 in the UK). It is inadvisable to use that as a default or dummy value here. – Gary Aug 8 at 0:59
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    I think this answer is bad advise. While the telephone number (123) 456-7890 looks like an invalid number to a human, it only looks so at second glance. Also, any automated system won't recognize it as invalid. It is entirely possible for a telco provider to assign this number to someone. There are actually people who suffer a lot from this. I once watched a report about the poor inhabitants of a house with the address "123 Main Street" in the post area code "12345" and the huge pile of junk mail they receive every day. Not so funny when they come from debt collectors or lawyers. – Philipp Aug 8 at 11:38
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    @Philipp Apparently the local post office that handles Zip Code 12345 in the US does receive a lot of bogus mail, though apparently nobody lives in the area the Zip Code designates since it belongs to the General Electric corporate headquarters. – nick012000 Aug 9 at 13:56
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    @Pryftan: 1 is the prefix to dial a non-local number (well, sometimes, it's more complicated than that). Introducing an area code starting with 1 would cause backwards compatibility problems, which the NANP has historically avoided (unlike, say, the British system which breaks back-compat all the time). – Kevin Aug 10 at 1:41

There aren't any international standards governing phone numbers, except for the internationally agreed country codes.

Each country has its own conventions regarding leading zeros, parentheses, and spacing.

The closest you'll get to an internationally acceptable number format would be:

+0011122223333

Where + denotes the international dialing prefix for your location, 00 the country code (can be fewer/more digits), 111 the 'area' code (can be fewer/more digits), etc.

If it's client-side phone number validation that you want, then check out this International Telephone Input jQuery plugin. It'll give you an idea of the complexity of the problem, if nothing else.

  • In case it's not obvious, using a nonexistent country code is actually a good idea (but still likely to end up in wrong places when people accidentally drop or misunderstand the meaning of the plus sign). – tripleee Aug 14 at 5:30

Rather than trying to anticipate all possible phone numbers and localisations, you could try to anticipate user questions instead.

Questions like “can I use spaces and dashes?” and “do you require a plus sign or double zero for international notation?”.

Every user should be able to ‘pass’ your validation rules in one go, so provide them with enough information to do so.

Having said that: a phone number consisting of all zeroes is probably bound to be fictional, always.

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    The user should not have to ask "can I use spaces or dashes?". The user should be allowed to use spaces or dashes (and parens or whatever) and your SW should figure it out. The international stuff is trickier... – user949300 Aug 7 at 21:43

protected by gnat Aug 8 at 16:45

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