Assuming you mean trace your IP to the physical address, they are only as accurate as the databases they pull their information from. The tracers I have worked with use the whois database provided through ARIN. They check to see City, Address, StateProv and Postal code. This works good if the person who has the allocation has kept their records accurate but in reality, this is not perfect. The only way they will ever get an IP -> Physical address is via a Subpoena to your local ISP.