Mobile applications such as Mr. Number and Call Control make it possible to block phone calls from specific numbers. Some phones have built-in tools that allow users to block specific numbers. Alternatively, some service providers offer call-blocking services for a monthly fee.
To block phone numbers using apps, users must install the app and choose the numbers they wish to block. Some apps, such as Mr. Number, let users block area codes. The settings for blocking specific phone numbers using the built-in tool is not universal. In some phones, a user can block by selecting a phone number and adding it to the block list. As of 2015, Verizon offers two plans for blocking five or 20 contacts for a monthly fee.