There are several ways to trace an unknown caller's number including using the appropriate star code, instant messenger services or free reverse look-up sites. These methods are free or low cost to use.
Star code 57 allows a user to directly trace a malicious caller. Instant messenger, or IM, services are another method for tracing unknown callers. In a two-step process, a user adds the unknown number to their IM contact list. Then, the owner's details will show on the caller's messenger page if the owner is registered. Social media sites provide another way to determine an unknown caller similar to IM services. Reverse look up sites offer simple to use search boxes for phone number identification.