How website visitor geolocation works.

How the lookup works

Every device on the internet has an address assigned by its network — a home broadband provider, a mobile carrier, an office, a data centre. Those address ranges are registered, and the registrations say roughly where the network operates.

A geolocation database maps ranges to places. When someone visits, the site looks their address up in that database. Nothing is read from the device itself, and no permission is requested, because nothing private is being accessed.

Why it is often wrong

The address describes the network, and the network is frequently somewhere else.

• • Mobile networks route traffic through regional hubs, so a phone in one town can resolve to a city an hour away.
• • A corporate VPN puts every employee at the company's head office, which may be in another country.
• • Business broadband is often registered to a provider's address rather than the customer's premises.
• • Cloud and privacy relays place the visitor wherever the relay is.

How precise it really is

Country is usually right. Region is often right. City is right often enough to be useful in aggregate and wrong often enough that you should not confront a visitor with it.

Street-level accuracy is not available from an address lookup at all. A tool showing a precise pin on a map is displaying the centre of a broad area with more confidence than the underlying data supports.

Using it sensibly

Read it in aggregate. If most of your visits resolve to two or three towns, that tells you where your market is and where a service-area page might earn its place.

Do not use it to decide something about one person. A single visit resolving to a nearby city is a hint, not a fact, and it is the kind of number that looks more solid on a dashboard than it is underneath.