USPhoneBook is a free online directory that helps people identify unknown callers and search U.S. phone numbers using publicly available records. Its reverse phone lookup lets users enter a 10-digit number, with or without dashes, and receive results in seconds without creating an account. The service says its database covers more than 2.5 billion records, including landline, mobile, residential, and business numbers across the United States.

Depending on the number and available records, search results may include a person’s or business’s name, current and previous addresses, carrier and line type, other associated phone numbers, possible relatives or associates, and email addresses. Users can also search by name or address. USPhoneBook presents the service as a resource for screening unfamiliar calls, checking contacts, reconnecting with people, and avoiding unwanted calls. It describes searches as private and says it does not store search history, share queries with third parties, or notify the person being searched.