What you should know about the UK phone number format

The UK phone number format can be a bit confusing at first because, unlike some other countries, UK phone numbers can have a range of digits—up to a maximum of 15 digits (although typical UK national significant numbers, after +44 and excluding the initial '0' trunk prefix, are 9 or 10 digits long).

In this blog post, we'll cover everything that you need to understand about the UK phone number format, including the types of UK numbers, examples of UK numbers, and how to choose the right UK number for your business. After reading this guide, you'll understand all aspects of a UK phone number so you can make sure that your customers can reach out to you in a timely manner.

How to format a UK phone number

When it comes to UK phone numbers, understanding the format and how to write them correctly is key. The UK telephone number format has up to 15 digits, starting with the country code (+44). Following this is the National Destination Code (NDC), often referred to simply as an “area code,” which is three to five digits that represent the local exchange or area of the caller. Geographic area codes vary in length (e.g., 020 for London is 3 digits; 0113 for Leeds is 4 digits; 016974 for Brampton is 6 digits, including the '0'). After this comes the Subscriber Number (SN), the length of which varies. In some cases, like with certain landlines, there may also be an optional extension after this number.

In order to write a UK phone number in an international format, it's necessary to drop the leading zero in the area code. UK phone numbers can be written in a standardized manner as per the E.164 guidelines, making it easier to identify phone numbers from various countries.

When writing a UK phone number, it's also important to consider how you should space out and punctuate your number, such as whether or not brackets are necessary and if you need hyphens between certain parts of your number.

Examples of UK phone numbers

To demonstrate how these parts combine to form a complete UK phone number, here is an example number: 020 7123 4567. In this instance, 020 indicates London as the area code, while 71234567 is the subscriber number. When written out in full using the E.164 standard format, it would look like this: +44 20 7123 4567. This same format works for both landline and mobile numbers in the UK.

Now, let's use the phone number for Dialpad UK as an example. Outside of the UK, the E.164 standard format would appear as: +44 203 048 4377. The area code is 0203, which represents London. The subscriber number is the last 8 digits, 0484377.

Types of UK phone numbers available

Now that you're familiar with how phone numbers are formatted in the UK, let's go over a few key types of phone numbers that you can get:

• Mobile numbers: mobile phone numbers in the UK start with "071" to "075" and "077" to "079" and have exactly 10 digits after the leading +44 country code or 0 trunk prefix..

• Freephone numbers: these non-geographic numbers are also known as "0800 numbers" and "0808 numbers". They are free call numbers that customers can dial without having to pay. 0800 numbers can have 9 or 10 digits after the leading 0 or +44, but 0808 numbers always have 10 digits after the leading 0 or +44.

• Geographic numbers: phone numbers starting with "01" and "02" represent a specific locale within the UK. The area code identifies the geographic location of the number – usually a city, town, or region – while the subscriber number follows it. For example, if your business is located in London, you might use an 020 area code followed by an 8-digit local number Numbers starting 01 can have either 9 or 10 digits after the leading 0 or +44. Numbers starting 02 always have 10 digits after the leading 0 or +44.".

• Non-geographic numbers: these may start with "0845", "0870", "0871", and more. They may have different cost implications for your customers depending on their network provider due to an additional access charge. 

  • Non-geographic numbers starting 084 or 087: these include "0843", "0844", "0845", "0870", "0871", and "0872". They may have different cost implications for your customers depending on their network provider due to an additional access charge as well as the regulated service charge. It's illegal for these numbers to be used for after-sales customer service by retailers, traders or passenger transport companies, or by financial services firms. Government guidance also does not allow usage by healthcare providers, government departments, their agencies and contractors, and other public service bodies. These numbers always have 10 digits after the leading 0 or +44.

  • Non-geographic numbers starting 03: these may start with "030", "033", "034", or "037" and always have 10 digits after the leading 0 or +44. These must be charged at the same rate as a call to an 01 or 02 geographic number and included in call allowances and discount schemes in the same way as 01 and 02 numbers. Numbers starting 030 are reserved for use by government departments, public service bodies, healthcare providers, schools and colleges, and by charities. Numbers starting 034 and 037 are reserved for migration from the exactly matching 084 or 087 number.

Choosing the right phone number for your business

Choosing the right phone number for your business is a decision you shouldn't take lightly. You want to find the most ideal combination that your customers will associate your brand with, and it may be troublesome to change your number in the future while ensuring that your customers dial the correct number. Figuring out the right number will enable customers to reach you easily and ensure that calls are routed correctly, so it's important to consider all the options available.

The location of your target audience should be taken into account when choosing a phone number format. If you're targeting customers who are mainly in the Manchester area, then you should opt for a UK number that has the area code 0161. But if most of your customers are in Edinburgh, then you should choose a 0131 number instead.

Aside from choosing the right phone number, you should also make sure that your business phone system supports your needs. Call routing capabilities can be immensely useful if your organisation has several teams that receive calls. Having features like custom interactive voice response (IVR) helps understand the purpose of a call and then route it to the right agent. This way, your calls won't be inadvertently diverted to the wrong place and cause confusion for your customer.

Or, if you find that your team spends a lot of time after each call to write down notes and follow-up action items, you can save them time with a tool like Dialpad that easily summarizes your call with the help of Ai.

By considering these factors carefully when selecting a phone number format for your business, you can ensure that customers can reach you easily and quickly without incurring any potential costs or loss for your business.