UK Phone Number Format: Everything You Need to Know

Senior Writer: Anant Berge

Published : May 27, 2025

Phone numbers around the world follow different formats. And, the United Kingdom is no exception to this. Understanding the UK phone number format is important, whether you’re calling locally or internationally, or just wish to share your number with others. 

Additional digits or unfamiliar codes generally cause confusion. If not dialed correctly, these may lead to failed connections. 

In this blog, we’ll break down how exactly UK phone numbers are structured. And what are the common and effective dialing practices, and most importantly, guide you through the nuances of making and receiving calls within and outside the UK.

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UK phone numbers consist of three main parts—the country code (+44), area code (2 to 5 digits), and subscriber number. The format varies between landlines, mobiles (starting with 07), and non-geographic business numbers (starting with 03 or 08). To dial abroad, omit the leading zero from mobile or area code and insert the country code. Correct formatting and knowledge of area codes result in successful calls locally and internationally.

Here’s a quick overview of the essential things to know about UK phone number formats:

• UK phone numbers have three parts: the country code (+44), area code, and local subscriber number.
• Landline area codes vary from 2 to 5 digits; mobile numbers start with 07 and have 9 more digits.
• Non-geographic numbers (starting with 03, 08, or 09) are used by businesses and aren’t tied to a location.
• When calling internationally, drop the leading zero from the area or mobile code and add the +44 country code.
• Writing and dialing UK numbers correctly prevents call failures—always include the right codes and check number lengths.

What is the UK Phone Number Format?

The UK phone number format refers to the way phone numbers are structured and written in the United Kingdom. It helps to ensure that the calls made are connected correctly, whether you are making a domestic or international call.

Talking about its structure and length, a typical UK phone number has three main parts:

• First, the country code. The UK country code is +44. It replaces the 0, which is used in domestic calls when dialing from abroad.
• Second, the area code. It is also called the national destination code. This one identifies a specific geographical location or mobile network operator. It can be 2 to 5 digits long, such as London’s 20 or a 5-digit code for smaller towns.
• Lastly, the subscriber number, also known as the local phone number. This is a unique number that is assigned to the phone line within that area code. 

Most UK numbers have between 10 and 11 digits in total (excluding the country code). Its length can vary depending on whether it’s a landline, mobile phone number, or a non-geographic number. 

Key Differences Between Mobile and Landline Formats

All the main components mentioned above have different formats. Understanding them is essential so that you dial the correct UK numbers. 

Below is a quick comparison of the key features of each type of phone number.

UK Phone Number Examples

When you have the correct information about the dialing format, one simple thing is ensured: that the calls are connected successfully. Each type of phone number in the UK has its own structure. 

Let’s dive a little further and understand each with a sample format example:

1. Landline Numbers

The UK telephone number format typically consists of an area code, which is followed by a local number. 

Let’s take a UK telephone number 

Landline numbers usually vary in length depending on the region. As shown above, London uses a 2-digit area code (20), while other areas may have longer area codes of 3,4, or even 5 digits. 

2. Mobile Numbers

UK mobile numbers always start with the prefix 07 when dialed domestically. This prefix is followed by a 9-digit subscriber number. 

Mobile numbers are usually 11 digits long in total (including the leading zero domestically) and are assigned to different mobile network operators that is based on the digits following the prefix. 

3. Business and Non-Geographic Numbers

When businesses want a phone number that is not linked to a particular city or region, they often use non-geographic numbers. These typically begin with prefixes like 03, 08, or 09.

Non-geographic numbers, companies generally use to offer nationwide services without revealing the physical location. They are commonly used for helplines, customer support, and business contact numbers.

Correct Ways to Write a UK Phone Number

How to write a UK phone number depends on whether you are writing the number for domestic or international use. Plus, where you choose to display it also matters like on websites, forms, or business documents. 

Domestic vs. International Formatting Rules

1. Domestic format: When you call within the UK, phone numbers include the leading zero in the area or mobile prefix.

Example: 020 7946 0958 or 07123 456789.

2. International format: When calling from outside the UK, the leading zero is dropped and replaced with the UK country code +44.

Example: +44 20 7946 0958 or +44 7123 456789.

Using the correct format that depends on the context helps you to make sure that the number can be dialed correctly from anywhere. 

Best Practices For Writing UK Phone Numbers 

• Always include the international country code +44 when you want to display UK numbers on websites, business documents, or any platform that international users can access.
• Use spaces to separate the country code, area code, and local number for clear readability.
• Avoid using dashes, dots, or unnecessary punctuation, because they can cause confusion or dialing errors.
• For online forms, follow the required input format. Here, you need to make sure that the country code is included if the number will be dialed internationally.
• For domestic communications, the national format with the leading zero is acceptable. Anyways it is advisable to double check the number length and format to avoid mistakes or mixing mobile and landline numbers. 

Recommended Read : 6 Best UK Virtual Phone Number Providers

UK Area Codes: A Quick Guide

In the UK mobile phone number system, area codes play an important role. They help in identifying the geographic location or specific service that is associated with the number. 

These codes come in different lengths– 3, 4, or 5 digits. Their length totally depends on the size and population of the area. 

How UK Area Code Lengths Vary by Region

• 3-digit area codes are usually found in major cities and metropolitan areas where there is a high volume of phone lines. For example, London uses the 020 area code. These shorter codes allow for longer local numbers within the area.
  

• 4-digit area codes cover medium-sized towns and regions. For instance, 0121 is the area for Birmingham, which is UK’s one of the largest cities outside London.
  

• 5-digit area codes are assigned to smaller towns and rural areas, where fewer phone numbers are required. An example is 01697, which covers parts of Northumberland and Cumbria.

Geographic Significance of Area Codes

Every area code is assigned to a particular geographic area in the UK. This enables phone companies to direct calls cost-effectively and enables one to know where a number is from or heading to based on where it originates. 

For instance, 0131 tells you it’s from Edinburgh, which is Scotland’s capital. The UK has multiple area codes that reflect its diverse regions. 

Besides geographic codes, there also exist non-geographic codes that serve businesses and special services, such as 03 and 08 numbers, which are not associated with any specific location. 

Most Commonly Used UK Area Codes

Below are some of the key area codes that you’ll often encounter:

These codes will help you to recognize the location from which the call is coming and make sure that you dial the number correctly.

How to Call UK Phone Number?

Dialing the UK phone number varies depending on certain factors like the type of call, your location, and the device, i.e., a mobile phone or a landline. 

Calling From Within The UK

If you are calling a UK phone number from the UK itself, then follow the steps below:

For Landline Calls:

1. Always dial the full number, including the area code.
2. The area code always starts with a zero.
3. For example, to call a London number, dial: 020 7946 0958.

For Mobile Calls:

1. Dial the full mobile number, starting with 07.
2. For example: 07123 456789.

Local Calls within the Same Area Code:

You might sometimes dial just the local number without the area code. However, it’s safer to include the full number (with area code) to avoid any confusion.

Calling a UK Number From Abroad

When you dial from abroad, you do need to add a couple of extra steps, but it is not difficult once you know what to do:

• Step 1: Dial the international call prefix of your country, also called the exit code. This prefix differs depending on where you’re calling from. For instance, America has 011, while most of Europe has 00.
• Step 2: Then, dial the UK country code, which is 44.
• Step 3: Next, dial the UK telephone number omitting the leading zero of the area or mobile code.  

So, to call the London landline phone number from the US, rather than dialing 020 7946 0958, you’d dial: 011 44 20 7946 0958

Likewise, to dial a UK mobile number from outside the country, remove the zero and dial: 011 44 7123 456789. This is essential for effective international dialing.

Steps For Landline Calls

Let’s look at the steps for calling from a landline phone:

• Step 1: Dial the full area code with the leading zero (e.g., 020) plus the local number when calling within the UK.
• Step 2: When you are calling from abroad, first dial your country’s international access code (such as 011 in the US or 00 in Europe).
• Step 3: Next, dial the UK country code +44.
• Step 4: Then, dial the area code without the leading zero, followed by the local number.

Steps For Mobile Calls

Let’s look at the steps for calling from a mobile phone:

• Step 1: Dial the full mobile number, which starts with 07, for domestic calls.
• Step 2: When calling overseas mobile phones, dial your country’s international access code.
• Step 3: Finally, dial the mobile number without the initial zero.

The table below provides a quick overview of common dialing formats with examples to make it easier to understand.

Common Mistakes While Dialing or Writing UK Numbers

Even a small mistake in dialing or writing a UK phone number can lead to failed calls or confusion. Here are some of the most frequent errors to watch out for:

1. Missing Area Code

 Omitting the area code, particularly for the fixed line numbers, is also quite a common mistake. Include the complete area code to guarantee that your call goes to the correct destination. 

2. Forgetting Country or Exit Code

When dialing internationally, it is important to include both your exit code (such as 011 or 00) and the international phone number for the UK (+44). Without these, you might not be able to get your call through. 

3. Inaccurate Digit Length

The UK phone numbers also differ in length based on region and type (landline or mobile). Trying to dial fewer or more digits may lead to mistakes or failing to connect the line.

4. Combining Mobile and Landline Formats

Dialing a mobile number using a landline format or dialing a landline number using a mobile prefix may lead to confusion. To avoid this, you have to just make sure that you use the appropriate UK phone number format when you dial the number. This distinction is vital for both domestic and international calls.

When these pitfalls are cleared, your calls go through quickly and effectively.

Conclusion

Dialing the UK phone numbers doesn’t have to be complicated anymore. Even if you want to make a phone call anywhere in the world or even nearby, knowing about the format and dialing these number correctly will smoothen your calling experience. 

A quick summary of the points to remember:

• Use the right country and area code.
• Enter the right number of digits.
• Double-check if it’s a landline or mobile number.

This way, your phone call will connect easily and without any interruption. Now, dialing UK numbers should feel easy and stress-free.

FAQs

1. How many digits are in a UK phone number?

UK phone numbers usually have 10 or 11 digits, which excludes the country code. The exact length depends on whether it is a landline, mobile, or non-geographic number. 

2. What’s the proper format for sharing a UK number internationally?

When you share a UK mobile phone number internationally, use the correct telephone number format by starting with the country code +44 and dropping the leading zero from the area or mobile code. For example, a London number would be written as +44 20 7946 0958.

3. Can I get a UK phone number from abroad?

Yes! Many telecom providers offer virtual UK phone numbers that you can get and use from outside the UK. These are often used by businesses and individuals who want a local UK presence without being physically there.

Updated : May 30, 2025

Anant Berge

Anant Berge is a B2B SaaS content writer who creates engaging, user-focused, and SEO-driven content for tech businesses. With a knack for simplifying complex ideas and a passion for storytelling, Anant crafts narratives that help brands connect with their audience through blogs and website content.

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