How to write phone numbers internationally (with examples for Africa, the UK, US and Canada)

Here is how to write a phone number internationally: start with a plus sign, then the country code, then the rest of the number without the leading zero you use at home. A Nigerian mobile that you dial locally as 0802 000 0000 becomes +234 802 000 0000. That one rule, plus a couple of habits about spaces, fixes most phone numbers on business cards, websites and email signatures.

This article shows how to write a phone number internationally in business email, with the rule, the reason behind it, a table of examples for Nigeria, Kenya, South Africa, Ghana, the United Kingdom and North America, and a checklist of mistakes to fix. The rules come from ITU recommendations and national regulator notices that we opened in October 2026. All sample numbers are made up.

Why you need to know how to write a phone number internationally

A signature is read by people in other countries, and by phones. If you write 0802 000 0000, a client in Nairobi or London cannot dial it as written. The zero is a national prefix that means “dial within this country”. From abroad, it must be replaced by a plus sign and the country code. That is why how to write a phone number internationally is worth settling once, for the whole company.

The plus sign matters because it stands in for the international dialling prefix, which differs from country to country. ITU-T E.123, the recommendation on how to print numbers, says the international prefix symbol should be a plus sign and should come before the country code. E.123 describes it as a reminder to dial the international prefix, which varies by country. A phone that understands the plus sign picks the right prefix for where the caller is.

How to write a phone number internationally: the ITU rules

We read two ITU texts for this article. The first is ITU-T E.164, which defines the international numbering plan. The edition we opened is E.164 (02/2026), which ITU marks as in force. It describes an international number as a country code followed by a national (significant) number, and it recommends that the national part should be no more than 15 minus the number of digits in the country code. It also says a country code is one to three digits long, and that a numbering plan does not include prefixes. That is why the leading zero is not part of the number you publish.

The second is ITU-T E.123 (02/2001), which ITU lists as in force and which covers how to print numbers. Its points on how to write a phone number internationally in a signature:

• The international prefix symbol should be the plus sign, placed before the country code.
• Parentheses should not be used in an international number. They are for the trunk prefix in a national number, such as (0).
• Grouping digits should be done with spaces. E.123 says only spaces should be used in an international number.
• A space should separate the country code from the rest, and the main break should come between the area or network code and the subscriber number.

That is how to write a phone number internationally by ITU’s rules: +234 802 000 0000 follows the guidance, while +234 (0) 802-000-0000 does not.

How to write a phone number internationally: examples for Africa, the UK, US and Canada

The table shows how to write a phone number internationally for seven countries, using made-up numbers. The “source note” column says what the regulator or ITU text we read says about that country. Where a source did not say something, the cell says so.

Country	Code	Written at home	International form	Source note
Nigeria	+234	0802 000 0000	+234 802 000 0000	NCC’s numbering notice, filed with ITU, says the national prefix is 0 and must not be dialled from abroad. Mobile numbers have 10 digits after the code
Kenya	+254	0700 000 000	+254 700 000 000	The Communications Authority notice lists mobile numbers as nine digits after the code, in ranges starting 7 and 1
South Africa	+27	082 555 0142	+27 82 555 0142	ICASA’s regulations say an international number follows E.164 (country code plus national number) and set geographic numbers at ten digits in their domestic form, whose ranges start with 0
Ghana	+233	024 000 0000	+233 24 000 0000	The NCA notices we read give mobile numbers as nine digits after the code, such as 24 followed by seven digits
United Kingdom	+44	07700 900123	+44 7700 900123	Ofcom’s notice to ITU shows UK mobile numbers as ten digits after +44
United States	+1	(415) 555 0142	+1 415 555 0142	E.123 notes that country code 1 equals the trunk prefix, so do not add another 1
Canada	+1	(416) 555 0100	+1 416 555 0100	The Canadian numbering administrator describes a three-digit area code inside a ten-digit North American plan

The national notices are listed on ITU’s national numbering plans page. Two cautions on that table. First, your own number may sit in a range we have not listed, so check against the regulator for your country. Second, the “written at home” column shows common local styles, and we have not found a regulator rule that fixes them. What matters is the international form.

One number, three jobs: show it, dial it, link it

Knowing how to write a phone number internationally covers two of the three jobs a signature number does. It must be readable, which is the spaces. It must be dialable from anywhere, which is the plus sign and country code. And on a phone it should be tappable, which means it needs a link.

The link form is simple: take the international number and keep only the digits and the plus sign. +234 802 000 0000 becomes tel:+2348020000000. emailfooter does exactly that when it renders a phone number in a signature: it builds the tel: link from the digits and plus sign, and shows the number as the person typed it. So tell staff how to write a phone number internationally when they type it. Our article on clickable phone numbers in a signature shows the link in more detail, and the piece on a phone number in an email signature covers which number to show, mobile or desk.

If you want people to message you on WhatsApp, how to write a phone number internationally still applies, but the link has its own format. See the WhatsApp number guide. For the bigger picture of getting a company’s email, domain and signature right, start with business email setup in Africa.

Mistakes to fix on sight

• +234 0802 000 0000. The 0 after the country code should go. This is the most common one.
• 00234 802 000 0000. Works from some countries, but not all. The plus sign works everywhere a phone can dial.
• (+234) 802 000 0000. Brackets are for the trunk prefix in a national number, and E.123 says not to use them in an international one.
• +234-802-000-0000. E.123 says to use spaces. Hyphens are not wrong to a human, but they are not the recommendation.
• Two numbers in one line with a slash. Put them on two lines, each with its own label.
• Letters in the number. Vanity numbers such as 0800 CALL NOW are not dialable from abroad.

How to write a phone number internationally for a Nigerian landline

If your office uses a Lagos landline, check how it is written. The NCC update filed with ITU in November 2023 changed fixed-line numbers: in its table, a Lagos number moved from 1 XXX XXXX to 201 XXX XXXX, with the old and new running in parallel from 10 July 2023 until 1 January 2024. A signature that still carries the old form is worth checking against your provider’s current number.

How to write a phone number internationally in a company signature

The practical way to keep numbers consistent is a house rule, not a reminder email. Pick one format, write it down, and make the signature tool follow it. In emailfooter, the company admin chooses whether the company number, the employee’s own number or both appear, and employees cannot override that. The employee types their number once, in the international form, and every signature shows it the same way. Here is what that looks like for a made-up Lagos company:

Example only. The company, person and numbers are made up. Both numbers use a plus sign, the country code and single spaces.

Here is a house rule for the whole company: “Write +, then the country code, then the number without the leading zero. Use single spaces. Nothing else.” That is one line, and it matches the ITU guidance above. Anyone who asks how to write a phone number internationally can be pointed to it.

Frequently asked questions

How to write a phone number internationally in an email signature?

Write a plus sign, the country code, and the number without its leading zero, grouped with spaces. For example, a Nigerian mobile 0802 000 0000 becomes +234 802 000 0000.

How to write a phone number internationally: do I include the zero after the country code?

No. The leading 0 is a national prefix. ITU’s Nigerian notice says it must not be dialled from abroad, and the same idea applies to other countries that use one.

What is the E.164 phone number format?

It is ITU’s international numbering format: a country code followed by a national number, usually written with a leading plus sign. ITU recommends that the national part is at most 15 minus the length of the country code.

Should I use brackets or hyphens in an international number?

ITU-T E.123 says brackets should not be used in an international number, and that only spaces should separate the groups. Follow that for signatures.

Is +1 the same for the US and Canada?

Yes, both use country code 1, and both use a three-digit area code followed by seven digits. Write +1, the area code, then the number.