How To Write Telephone Numbers

The way that telephone numbers ("phone numbers") are commonly written is ambiguous and introduces confusion. Consider the following Adelaide phone number. This number would typically be written as:

82326262

While perfectly reasonable, this number is useable only to someone in South Australia. To make it less ambiguous, we could add the area code "8":

   8 82326262

The above is now a number that is unambiguous within Australia. However, if someone actually dialed the number, they would not get through because in order to dial a non-local number in Australia, you have to prefix the number with "0"! So, usually, when a number such as the above is expressed, it is written as:

   08 82326262
or
   (08) 82326262

This is now unambiguous and dialable within Australia, but if someone not in Australia tries to dial the number after accessing the Australian phone network from another country, the leading "0" will cause the access to fail.

To make the number less internationally ambiguous, one can prefix the phone number and area code with a country code:

   61 8 82326262

Confusingly, some people feel that they should still drop a hint to their compatriots that a zero is required if they are dialing the number from Australia, so they write:

   61 (0)8 82326262

One sees the parenthesized "0" in UK phone numbers quite often.

One problem with the above is that it's not directly dialable because, in any country, you need to prefix the number with your international access prefix. In Australia, the prefix is "0011" so some people write their number like this:

   0011 61 8 82326262

However, this form won't work when dialed from other countries where the international access prefix is not "0011". Furthermore, prefixing the number with the local international access prefix can confuse those in other countries by forcing them to play a guessing game about where the international access prefix ends and the country code begins, particularly, if the number is run together like this:

   001161882326262

Enough! Here's How To Do It Properly!

To avoid all of the above confusion, it's best to write your phone number in a standard form that seems to be recognised internationally. The form is as follows:

   +<CountryCode> <AreaCode> <LocalNumber>

So an example is:

   +61 8 82326262

The "+" represents the international access prefix (which will vary from country to country). For example, in Australia the "+" means "0011". A space is placed between the country code and the area code, and between the area code and the local number, so that readers can determine how to dial the number if they are in the same country or area.

I like to separate the two groups of four digits in the local number by a hyphen because it makes the local number easier to read. I don't know how "standard" this is.

   +61 8 8232-6262

Sometimes people use a space to separate two parts of the local number, but I think that this introduces ambiguity.

US Phone Numbers

Americans almost always write their phone number in the following form:

   (555) 123-4567

This assumes that the person telephoning knows that the number is in the US and that the country code for the US is 1. To avoid ambiguity, US numbers should be written in the standard form like this:

   +1 555 123-4567

A Note On Technology Origin And Address Incompleteness

It is interesting to note that countries that invent a communications technology tend to end up being the only country not to specify themselves in the communication address. Here are three examples:

Stamps: The English invented the postage stamp, and, until very recently were apparently the only country not to put the country name on their stamps.

Telephone: The USA invented the telephone, and nearly all US citizens do not prefix their telephone numbers with their country code, even in email signatures.

Internet domain names: The USA invented the internet and initially used .com and .org and .net rather than .com.us and .org.us and .net.us for the USA. This initial effect was rapidly overtaken by the rate of growth of the internet and these countryless top-level domains now mean "international".

Ross Williams (ross@ross.net)
4 February 2002