Some mobile phone providers offer free, unlimited mobile-to-mobile calls within the same network. Calling someone on a different network will cause you to use the minutes included in your calling plan or may cost an extra fee. Finding a person's mobile phone service provider is an excellent way to ensure that the call you are making is included in your mobile-to-mobile minutes.
Go to the Fone Finder website and enter the mobile phone number.
Click "Search by Number."
Click the link under "Telephone Company Web Link" to view the name of the person's mobile phone carrier.
Go to the Phone Validator website.
Enter the mobile phone number into the field and click "Search."
View the mobile phone service provider. You will find this information listed next to "Phone Company."
You can also check your mobile phone bill. If you were not charged minutes for a call you made to someone during peak hours, then you share a mobile phone provider with that person.