If you want to find out who is calling when you don't recognize a number on your caller ID, you can do a reverse phone number search to find out. You get all the information you need without paying a fee or enlisting additional services. This only works if the phone number in question is a listed number.
Navigate to whitepages.com.
Enter the phone number that you are tracing, including the area code and separated by dashes, in the Reverse Phone box.
Hit "Find." A new page will open, displaying any available information about the phone number, such as name and street address.