In order to find a person's cellphone number, use online resources such as The National Cellular Service Directory's website, search engines and social media profiles. Most cellphone lookup services and online profiles provide information, such as cellphone numbers of users who opt to provide the information.
The National Cellular Service Directory's website is an opt-in database to locate cellphone numbers. They do require users to register and charge for the service, but they currently offer a promotion for 1 free hour a day of usage with an account. Search engines and social media profiles, such as Google or LinkedIn, may also provide cellphone numbers for registered user's profiles who provide that information.