How accurate is IP-based Geolocation Lookup?

By finding IP address of yourself or a person you wish to lookup, the geolocation lookup tool provide you with an estimate of where this IP address is located. American Registry of Internet Numbers, also known as ARIN, maintains the Whois Database containing contact and registration information for IP addresses. The companies requiring IP addresses obtain and register them with ARIN, and those IP addresses obtained are assigned to their users and customers. Internet Service Providers (ISPs) assign a dynamic IP address to a user when their customers connect to the Internet. Since a company may be located throughout a large region (or a country), the accuracy of geolocation may vary depending on how they assign them to their users.

What makes more difficult is the IP addresses maintained by cell phone providers. As cell phones roaming around cell towers, they obtain new IP address as users move. The wireless telephony providers service their users nationally, and the pool of IP addresses used doesn't necessarily provide accurate geolocation. So, how accurate is IP Location?

There are more than a dozen IP geolocation database providers, and the accuracy of each provider is different. Each provider gets their IP address information from ARIN, but the assignment changes regularly as some companies release unwanted IP addresses and others obtain a new block of IP addresses. Also, the blocks of IP addresses assigned to many companies can, in turn, assign them to their users however they want without geographic boundaries. This makes very difficult to pinpoint geolocation of an IP address. Also, the accuracy of geolocation data differs by providers so care should be given when picking a data source. We, IPlocation.net, offer data from a handful of companies so you'll have access to a few whom you can try.

The rough measure given above is based on the claims made by some of the data providers, and the actual result may vary from provider to provider. Also, looking up a geolocation from your cell phone may result in less accuracy than home-based IP address. In addition, users who connect through a VPN or similar privacy service such as PlanetVPN will appear to be located where the VPN exit node is. This can substantially reduce the usefulness of IP-based geolocation for identifying a user’s true location.

Can you locate a person from an IP address?

Unlikely. However, you may be able to identify a person from an IP address if you know the IP address and exact time when the IP address is used. Most Internet Service Providers keep a log of how IP addresses are assigned to users, so you can request to identify the person if you have the subpoena or authority from law enforcement. The usage log will determine the IP address assignment to the user's account, and reveal owner's name and contact information.