Simple guide to calling a London number from US, Australia, Europe, anywhere

New for 2018: This page now automatically detects where you are visiting from and provides the full number to dial either a fixed line or a mobile number in London from anywhere in the world. This has been the most popular page on my blog since 2010. I hope it helps you get through to that London number wherever you are.

To call London (or in fact any UK number) from overseas, you first need to know the International Direct Dialling code (IDD) for your country. We have detected you are visiting this page from United States.

In this example, we will look at calling the London fixed line number 020 7123 4567.

If you are calling from United States, then we have calculated you should dial the full number as shown below:


This number sequence is formed of:

[International Direct Dialling code] + [UK country code 44] + [UK number less the leading zero 20 7123 4567]

Note that when calling international numbers you always DROP the leading zero of the local number you wish to dial.

In the above example, the country code shown is 44 for the UK. The country code is different for every country.

You can find any country code from the dropdown list below, it is the +xx number next to the flag: [contact-form-7 id=”57893″ title=”country-code”]

For a UK mobile number, these always start with 07, and may be written in the following ways:

07881 234 567 or +44 (0) 7881 234 567 or +44 7881 234 567 (the full international number)

Note the + symbol means you have to add (+) your International Direct Dialling code (IDD) before the number. In this case, the IDD has been automatically calculated and inserted in each of the examples here.

For the UK mobile number example, calling from United States, we have calculated you would dial the following number


Wrong country detected?
In case the auto-detection of your location on this page has not worked and you are not calling from United States, then to call the UK mobile number 07881 234 567 from the US (for example) you would dial

011  44  7881 234 567

IDD (for US)  + UK COUNTRY CODE 44  + LOCAL NUMBER (less the leading zero)

TOP TIP: On your mobile, you can substitute the international access code with the + sign.
On an iPhone, or Android phone, long press the 0 key for a few seconds to bring up the + symbol on the numeric keypad.

The GSM standard provides for the + sign signalling you want to make an international call anywhere in the world, so if you were a US traveller in the UK and wanted to call back home, you would simply use the + symbol then the country code for the US (1), then the number.

This makes things a lot easier because in each country the international access code is different. In the UK it is 00, in Australia 0011, and in the US it is 011.

TOP TIP: If you travel a lot, then you can edit all of your phone numbers to always dial the full international number wherever you are in the world.

I have converted my entire phone book so that when I need to call someone I get straight through, and do not need to remember any international direct dialling codes, or country codes wherever I am in the world.

In the UK mobile example above, 07881 234 567 would simply be stored as +44 7881 234 567 in my phonebook and this works anywhere in the world, even if you are in the UK and dialling a local number.

Hopefully, those searching for “London Calling” or “calling a london number” on Google will now find what they are looking for. If you are interested in digital disruption, then why not have a look at the rest of this site, or follow me on twitter @andrewgrill, or other social networks at the top right of this page.

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Based in London, Practical Futurist and former Global Managing Partner at IBM, Andrew Grill is a popular and sought-after presenter and commentator on issues around digital disruption, workplace of the future and new technologies such as blockchain. Andrew is a multiple TEDx and International Keynote Speaker.