Reverse phone lookup refers to the process of finding out who has registered a particular phone number. This can work with any number, whether it’s a cell phone or a landline and whether it’s listed or unlisted. With this service now widely available through several different channels, you’ll never have to guess who is that annoying caller in the middle of the night, who is making prank calls to your house, or who is calling your boyfriend or child.

The following are four steps to help you use reverse phone lookup services online to find out who owns the number that is bothering you.

#1: Use online phone directories.

The fastest way to find out who is behind a number is to look up the number in online phone books, such as the White Pages. This is a starting point, but will only work if the number in question is a listed landline number. If you know it is a cell phone, you can skip this step as phone book companies do not have access to cell phone numbers.

As of now, there is no central directory of all cell phone numbers like there is for listed landline numbers. Some cell phone providers have their own user directories, but these are not generally made publicly available.

#2: Use Google or another search engine.

This is another hit-or-miss reverse phone lookup strategy, but it’s also another free strategy, so it’s worth a try. Open Google or another search engine if you prefer and do a quick search for the phone number. If the number appears on any website, blog, or social networking site like Facebook, it should display it.

If the number corresponds to a business, you are more likely to have success with this reverse phone lookup strategy, since most businesses have websites and advertise online, often listing their contact information, including a website Web. If the number is someone’s personal landline or cell phone number, just hope that it was posted on the web somewhere at some point. If not, you will need to move on to the next option.

#3: Free reverse phone lookup services.

Your next option is to find a real reverse phone lookup service that provides basic information for free. These services aren’t as useful as the ones you have to pay for, but it’s worth making one last push before moving on to step four.

If you haven’t been able to find the number through the first two steps, don’t hold your breath to find it through a free service. They usually use phone books and the same kind of publicly available information you’ve already searched for, but give it a try before you get to the final step. You never know!

#4: Reverse Paid Phone Lookup Services.

If you’ve gotten to this step, you’re probably dealing with a cell phone number that has never been posted online or a landline number that someone paid to keep off the list. There are some good reverse paid phone lookup services that can give you information on unlisted numbers and cell phones. They will tell you who the number is registered to, where it was registered (state and city), and sometimes additional information will be included.