Websites you access can determine your physical geographical location in a few ways. Your IP address reveals your general area—unless you use a VPN. Websites can also ask for a more precise location.
What Your IP Address Tells Websites
When you connect to a website, that website then sees your IP address. Your computer connects to the website’s IP address, and the website sends data back to your IP address. Packets are transmitted through network routers, and the IP address on those packets tells the routers where they need to go.
However, websites can’t trace that unique IP address to your physical home or business address. Instead, websites can tie your IP address to your internet service provider, city, region, and even possibly your ZIP code. This is why you see ads for local businesses in your area online, for example.
For instance, if you go to a website like this IP Location Finder, you’ll see that the website can use your IP address to determine the name of your internet service provider, along with your local city, region, and country.
But that’s all the information websites can get. They don’t know your physical address within that city or region.
While this usually works well, it isn’t perfect. Websites may sometimes think your home IP address is in a different city from the one you live in, for example.
Websites Can Ask for Your Precise Location
Websites can sometimes see your precise physical location, but they have to ask you first. When a website asks for your location, modern web browsers show a permission prompt.
For example, a weather website may want to show you the weather down to your precise location, or a retail store’s website might want to show you all its nearby stores and their precise distance from your location. A mapping website could use your physical location to provide navigation directions and so on.
When a website wants this access, you’ll see a prompt in your browser asking for it. If you give the website permanent access to your location, it can always see your location without having to ask again whenever you load the website in your browser.
To check which websites can see your location, you’ll need to check your browser’s settings. For example, in Chrome, click Menu > Settings > Site Settings > Location. You’ll see a list of websites that are allowed to see your location under the “Allow” heading.
You’ll also see a placemark indicator in Chrome’s address bar when a website has accessed your location. Other browsers work similarly, providing a visual indication that this has occurred on the current page.
How Your Devices Can Find Your Precise Location
If you use a phone or tablet with a built-in GPS radio, your precise location is determined using GPS, and then provided to the website. That’s how it works with location services in apps on iPhone, iPad, Android, and even some Windows 10 tablets.
But what if you’re just using a computer? Well, your device can use Wi-Fi-based location services. By scanning for a list of nearby Wi-Fi networks and their relative signal strengths, your precise location can be estimated and then provided to the website if you choose to allow it. This same feature is used on mobile platforms when there isn’t a solid GPS signal.
And what if you’re using a computer without a Wi-Fi radio—in other words, just a PC plugged into an Ethernet cable? In this scenario, you won’t be able to give a precise physical location to a website. If you try, you’ll just end up providing a more general location based on your IP address—likely just the city or area you live in.
Big Data and Cross-referencing Location Information
By the way, it’s technically possible for websites and advertising networks to cross-reference data. They might be able to tie your IP address to a physical address, for example.
For instance, let’s say that you have multiple devices on your network, and they all share a single IP address—the usual situation. Now, let’s say one device on the network goes to a particular website, which we’ll call “ExampleCorp,” and gives it access to your precise location. ExampleCorp now knows the current physical address associated with the IP address.
Now, let’s say that you head to the ExampleCorp on another device and deny it access to your precise location. ExampleCorp’s website may not act like it has your precise location. However, ExampleCorp knows your IP address, and it knows that the IP address was tied to a specific location.
We don’t know how many companies are tying this data together in this fashion. However, some websites and advertising tracking networks likely are. It’s certainly possible with the technology they have.
VPNs and Hiding Your Location
When you access a website through a VPN, you connect directly to the VPN server, and the VPN server connects to the website on your behalf. It functions as a middleman, passing traffic back and forth.
So, when you access a website through a VPN, the website will see that VPN’s IP address, but it won’t know your IP address. This is how VPNs allow you to bypass geographical restrictions on the web. If a website or streaming service is only available in the U.K. and you’re in the U.S., you can connect to a U.K.-based VPN and access the website. After all, the website thinks you’re connecting from the VPN’s address in the U.K.
Update: Note that, if you’re connected to a VPN and give a website permission to see your physical location in your web browser, that website may be able to see your real location. Your web browser will still be able to determine your location from nearby Wi-Fi access points (if it has a Wi-Fi radio) or GPS (if your browser is running on a device with built-in GPS hardware) and report it to the website. This is only the case if you give the website access to see your location—if not, the website will have to go by your IP address, which will appear to be the VPN’s IP address.