UK Phone Number Format Explained — Complete Guide with Examples
UK phone numbers follow a structured format managed by Ofcom, the UK's telecommunications regulator. Whether you are calling a London landline, a mobile, or dialing into the UK from abroad, understanding the format helps you get the number right every time. This guide breaks down every type of UK phone number with clear examples.
UK Phone Number Structure
All UK phone numbers start with a trunk prefix of 0 when dialed domestically. This prefix is dropped when dialing from outside the UK. A standard UK number has 11 digits in total (including the leading 0).
The general structure is:
The area code length varies between 2 and 5 digits (after the 0), and the local number fills the remaining digits to make 11 total. For example, London uses a 2-digit area code (20) with an 8-digit local number, while smaller towns may have a 4 or 5-digit area code with a shorter local number.
Landline Number Format
UK landline numbers are geographic — the area code tells you which part of the country the number is associated with. Area codes always start with 01 or 02.
London Numbers (020)
London uses the area code 020, followed by an 8-digit local number. The local number can start with either 3, 7, or 8.
Despite how people sometimes write it, London numbers are not 0207 or 0208 — the area code is always 020. The 7 or 8 is part of the local number.
Other Major Cities
Cities outside London typically have 3, 4, or 5-digit area codes:
Mobile Number Format
UK mobile numbers always start with 07, followed by 9 more digits (11 digits total). The digits after 07 originally indicated the mobile network, but due to number portability, this is no longer a reliable way to identify the carrier.
Common Mobile Prefixes by Network
While numbers can be ported between networks, these prefixes were historically assigned to:
- 074, 075, 07624 — O2 / Telefonica
- 076, 077 — Vodafone
- 078, 079 — Three / Hutchison
- 073 — EE / BT Mobile
International Format (+44)
When writing a UK number in international format, replace the leading 0 with +44:
| Type | Domestic | International |
|---|---|---|
| London landline | 020 7946 0958 |
+44 20 7946 0958 |
| Birmingham landline | 0121 496 0813 |
+44 121 496 0813 |
| Mobile | 07700 900123 |
+44 7700 900123 |
| Manchester landline | 0161 496 0274 |
+44 161 496 0274 |
Key rule
Never include both the 0 and the +44. It is either 020 7946 0958 (domestic) or +44 20 7946 0958 (international) — never +44 020 7946 0958.
Formatting Rules
- The total digit count is always 11 for domestic format (including the 0)
- Use spaces to separate the area code from the local number for readability
- Do not use dashes or parentheses — UK convention uses spaces only
- When storing numbers in databases, use the E.164 format: +44 followed by digits with no spaces (e.g.,
+447700900123) - The leading 0 is a trunk prefix, not part of the actual number — drop it in international format
Common UK Area Codes
| Area Code | City / Region | Example Number |
|---|---|---|
020 | London | 020 7946 0958 |
0121 | Birmingham | 0121 496 0813 |
0131 | Edinburgh | 0131 496 0274 |
0141 | Glasgow | 0141 496 0358 |
0151 | Liverpool | 0151 496 0421 |
0161 | Manchester | 0161 496 0537 |
0113 | Leeds | 0113 496 0614 |
0114 | Sheffield | 0114 496 0729 |
0115 | Nottingham | 0115 496 0835 |
0116 | Leicester | 0116 496 0942 |
0117 | Bristol | 0117 496 1058 |
0118 | Reading | 0118 496 1174 |
029 | Cardiff | 029 2049 6123 |
028 | Northern Ireland | 028 9049 6274 |
01234 | Bedford | 01234 567890 |
01225 | Bath | 01225 567890 |
01223 | Cambridge | 01223 567890 |
01273 | Brighton | 01273 567890 |
01332 | Derby | 01332 567890 |
01392 | Exeter | 01392 567890 |
01603 | Norwich | 01603 567890 |
01752 | Plymouth | 01752 567890 |
01865 | Oxford | 01865 567890 |
01904 | York | 01904 567890 |
How to Dial UK Numbers from Abroad
The process depends on which country you are calling from:
| Calling From | Dial Sequence | Example (London) |
|---|---|---|
| United States / Canada | 011 + 44 + number |
011 44 20 7946 0958 |
| Australia | 0011 + 44 + number |
0011 44 20 7946 0958 |
| Europe (most countries) | 00 + 44 + number |
00 44 20 7946 0958 |
| Any country (mobile) | + 44 + number |
+44 20 7946 0958 |
On a mobile phone, you can always use the + prefix instead of the international access code. This works from any country.
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Frequently Asked Questions
A UK phone number typically has 11 digits when dialed domestically, including the leading zero. For example, a London number is 020 XXXX XXXX (11 digits) and a mobile number is 07XXX XXXXXX (11 digits). When written in international format with +44, the leading zero is dropped, making it 10 digits after the country code.
+44 is the international dialing code for the United Kingdom. When calling a UK number from abroad, you replace the leading 0 with +44. For example, the domestic number 07700 900123 becomes +44 7700 900123 in international format. The plus sign represents the international access code.
To call a UK number from the US, dial 011 (the US international access code), then 44 (the UK country code), then the UK number without the leading zero. For example, to call the London number 020 7946 0958, you would dial 011 44 20 7946 0958 from a US phone.