The Hidden Geography of the Internet How IP Geolocation Works — From ARPANET to Modern Geo-Aware Services

You visit a website. It shows you the weather in your city. It offers prices in your local currency. It displays the correct language. The website did not ask you where you are. It knows. The technology is IP geolocation — mapping your IP address to a physical location. An IP lookup tool shows you what the internet knows about your location. The accuracy may surprise you.

How IP Geolocation Works

IP addresses are not random. They are allocated in blocks by regional registries. The registry for North America (ARIN) allocates blocks to ISPs. The ISPs allocate blocks to regional networks. A block of IPs in Dallas, Texas, is assigned to a specific ISP in that region. The geolocation database maps the IP block to Dallas. The mapping is accurate at the city level for most residential IPs. It is less accurate for mobile IPs (which route through regional hubs) and corporate IPs (which may route through headquarters in a different city). The accuracy is: city-level: 95%+ for residential IPs, 70-80% for mobile IPs, and 50-60% for corporate VPNs. Street-level: almost never. IP geolocation maps to a city, not a street address.

The IP lookup tool shows you what the internet knows about your location. The result is a city — not a street address. The map shows the approximate location. The accuracy varies. The world map explorer shows the geographic context. The global weather checker uses your location for weather data. The combination of IP geolocation and these tools creates a personalized web experience. The technology is remarkable. The limitations are important to understand.