For a UK landline, the area code tells you where a number is registered. It's the digits between the leading 0 and the rest of the number, for example the 020 in 020 7946 0018, which is London. Mobile numbers, and numbers starting 03, 07, 08 or 09, don't work the same way. They're not tied to a location, so there's no area code to look up.
This guide explains what you can genuinely tell from a phone number, and where the trail runs cold.
How can you tell where a landline number is from?
Landline numbers starting 01 or 02 are geographic. The digits straight after that 0 identify a specific area, generally a city or a large town rather than a council boundary. A few examples:
| Area code |
Area |
| 020 |
London |
| 0113 |
Leeds |
| 0114 |
Sheffield |
| 0117 |
Bristol |
| 0121 |
Birmingham |
| 0131 |
Edinburgh |
| 0141 |
Glasgow |
| 029 |
Cardiff |
| 01223 |
Cambridge |
| 01224 |
Aberdeen |
The quickest way to check a code is T2K's own area codes finder, which lists every UK area code alongside the towns and cities it covers. This list is set out by Ofcom, the UK's telecoms regulator, and it only covers 01 and 02 numbers, since anything else isn't linked to an area in the same way.
Worth knowing: the area code tells you where the number is registered, not necessarily where the person is sitting right now. Call forwarding and cloud phone systems mean a Manchester number can ring a phone in Truro without either party noticing.
What do 03, 07, 08 and 09 numbers tell you?
Nothing about location. These ranges are called non-geographic numbers, and each prefix means something different:
| Prefix |
What it means |
Tells you the location? |
| 03 |
Non-geographic, charged the same as an 01 or 02 call |
No |
| 07 |
Mobile or personal number |
No |
| 08 |
Freephone (0800, 0808) or special rate (0843, 0844, 0870 and similar) |
No |
| 09 |
Premium rate |
No |
A 03 number is often used by businesses with multiple offices, so one number reaches whichever site or department picks up next, regardless of where the caller or the business actually is. Our guide to business phone lines covers when a 03 number makes sense.
Can you find out exactly where a mobile number is registered?
Not reliably. UK mobile numbers have never been tied to a geographic area. The first few digits after 07 originally identified which network issued the number, but number porting means a mobile can move between networks and keep its number, so even that clue is now unreliable.
Reverse phone lookup services exist and will sometimes return a name or a general description, such as whether a number is likely to be a landline, a mobile or a known nuisance caller. Treat the results with some caution. Most of these services rely on user reports rather than official data, and paid versions don't guarantee an accurate result.
Why might a caller's area code not match where they actually are?
A few reasons, and only one of them is a problem:
- Call forwarding and cloud phone systems. A business can have a London number that rings a phone system based anywhere in the country. This is normal and not a sign of anything wrong.
- Choosing a number deliberately. Many businesses take out a number in an area they want a presence in, even if their office is elsewhere. We cover this below.
- Caller ID spoofing. Scam callers can display a false number on your phone, sometimes one that looks local to you specifically, to make the call seem more trustworthy. If a call felt wrong, Ofcom has advice on unwanted and scam calls worth reading.
How can businesses use area codes when choosing a phone number?
A phone number is part of how customers judge a business before they've spoken to anyone. A local area code can signal that a business is based nearby, which still carries weight for tradespeople, local services and regional offices, even though the call itself might be answered anywhere.
With a hosted phone system, a business isn't limited to the area code of its office. You can hold numbers for several towns or cities and route them all into the same phone system, so calls to a Leeds number and a Bristol number both land with the same team. Our telephone numbers by area code page lists which codes are available, and our guide to choosing business telephone numbers explains the options in more detail, including 0800 and 03 numbers.
If you're also allocating individual numbers to staff within one system, it's worth reading what a DDI number is, and if you're moving to a cloud phone system, what is a VoIP phone number? explains how VoIP numbers work compared with a traditional line.
Frequently asked questions
How do I find out who owns a phone number?
For a UK landline, T2K's area codes finder will tell you the general area straight away. It won't tell you the specific person or business behind the number, since there's no single official directory that covers every UK number that way. A search engine or a reverse lookup service may surface a business name if the number is publicly listed.
Can I trust caller ID to show the real number?
Mostly, yes, but not always. Legitimate businesses using a hosted phone system will show their real business number. Scam callers can spoof a number to display something else entirely, including a number that looks like it's local to you. If in doubt, don't call the displayed number back directly, and look up the organisation's number independently instead.
How do I block or report a scam call?
Most mobiles and VoIP handsets let you block a number directly. You can also forward scam texts to 7726 and report scam calls to Ofcom or your provider. If you're moving to a new phone system, ask your provider what call-blocking and reporting features are included, since this varies between systems.
Can I get a local number for my business even if I'm not based there?
Yes. This is common practice with hosted phone systems, and it's legitimate as long as you can actually provide the service you're advertising in that area. Numbers route through to wherever your phone system is hosted, regardless of the area code shown.
Do 03 numbers cost more to call?
No. Ofcom requires 03 numbers to cost the same as calling an 01 or 02 landline number, including from inclusive minutes on mobile and landline contracts. They're not the same as 08 numbers, which can cost more depending on the range.
Choosing the right numbers for your business
Whether you need one local number or several across different towns, T2K can set up a phone system that handles them all in one place. Take a look at our available telephone numbers by area code, or use the Phone System Finder to see which system fits your business, and get independent advice if you'd rather talk it through.
