How to use a phone number look-up service

You do not need to pay to look-up for phone numbers in your area. BT has phone directories that will let you look-up for land line phone numbers for people who have agreed to let their phone numbers be published. You can find phone numbers in the United States by using online phone directories. If people choose to keep their numbers unlisted, they will not appear in directories.

BT directory basics

You cannot find mobile phone numbers unless the owner allows them to be in directories, but you can find land line phone numbers unless the owner excludes them from the directory. When you are using computer-based telephone number look-ups, you need to have some basic information, such as how to spell the person's last name.
BT website
When you are looking-up for UK phone numbers, you can go to the BT website and use their free online tool. BT will want to know the last name and the city for the phone number, or at least, the post code and the last name. Sometimes, you can just spell the beginning of the last name and get all of the results for similar names. To look-up for residential numbers in the BT phone book, go to BT.com and click on directory enquiries. You will then, see the text boxes, and the site indicates which information is required.

Problems finding phone numbers

If you have an unknown number that is calling your mobile phone, dialling it back (or texting it) is the fastest way to find out who is calling you.
Reverse phone look-ups
Reverse phone look-ups can find residential and business phone numbers, but they usually cannot find business fax numbers or mobile numbers. If you are not getting results from your searches, you should check to see if the number is not a mobile number. You can usually learn a mobile number's carrier from the prefix. Orange is 07, for example. Searching by the last name
If you are not having luck with the BT telephone directory, remember that the phone could be listed under a home-owner last name, such as a step-parent, or a parent's name if they set up a land line phone for a student who is at university. If you decide to pay a service to locate a phone number for you, be sure that they will only charge you if they are able to give you the correct number.