# how does my PC's web browser know my location? **URL:** \ **Category:** Factual Questions\ **Created:** [December 31, 2011, 4:19pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955 "2011-12-31T16:19:48Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![JoelUpchurch](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@JoelUpchurch](https://boards.straightdope.com/u/JoelUpchurch)\ **Post date:** [December 31, 2011, 7:11pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/21 "2011-12-31T19:11:48Z")
> [@doubled](#): > > Very skeptical of that theory. I live in a high-rise building in New York – pretty sure my wifi signal isn’t strong enough to be intercepted at street level. I’m way too many floors up. IIRC, your wi-fi signal can be detected at several times the distance that it can used for communication. It only needs to pick up the MAC address to use it for location services. ---
**Author:** ![standingwave](https://avatars.discourse-cdn.com/v4/letter/s/9de0a6/32.png) [@standingwave](https://boards.straightdope.com/u/standingwave)\ **Post date:** [December 31, 2011, 7:27pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/22 "2011-12-31T19:27:05Z")
> [@BorgHunter](#): > > This is untrue. Your user agent string contains your OS and browser + version, and that’s about it. The link you posted retrieves your location using IP address geolocation, and your screen resolution through JavaScript. Ah, I thought it was all part of the user agent or inferred from the user agent. Still, that represents a lot of information that a site can gather from your browser. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 31, 2011, 11:15pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/23 "2011-12-31T23:15:49Z")
My wifi-only iPad uses Skyhook as well. As long as enough people name their nets something other than Linksys or 2wire, it works pretty well. What are the chances that there are two places in the US where networks named Westell2689, adobonet, MikeG and ourhome can be received? They’ve got my home location almost exactly, thanks to my neighbors’ use of unique names, but there are some things that will confuse it. When I was in the hospital a while ago, the whole campus had a managed, yet public, net. As the hospital campus covered several city blocks, the location service had a 5-block uncertainty radius due to the massive footprint of that one SSID. ---
**Author:** ![JoelUpchurch](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@JoelUpchurch](https://boards.straightdope.com/u/JoelUpchurch)\ **Post date:** [January 1, 2012, 7:00am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/24 "2012-01-01T07:00:50Z")
> [@gotpasswords](#): > > My wifi-only iPad uses Skyhook as well. As long as enough people name their nets something other than Linksys or 2wire, it works pretty well. What are the chances that there are two places in the US where networks named Westell2689, adobonet, MikeG and ourhome can be received? > > They’ve got my home location almost exactly, thanks to my neighbors’ use of unique names, but there are some things that will confuse it. When I was in the hospital a while ago, the whole campus had a managed, yet public, net. As the hospital campus covered several city blocks, the location service had a 5-block uncertainty radius due to the massive footprint of that one SSID. Skyhook uses Mac addresses, not SSID to identify individual routers. [http://en.wikipedia.org/wiki/Skyhook\_Wireless](http://en.wikipedia.org/wiki/Skyhook_Wireless) ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [January 1, 2012, 7:16am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/25 "2012-01-01T07:16:00Z")
> [@JoelUpchurch](#): > > Skyhook uses Mac addresses, not SSID to identify individual routers. > > [http://en.wikipedia.org/wiki/Skyhook\_Wireless](http://en.wikipedia.org/wiki/Skyhook_Wireless) Apple hasn’t used Skyhook since [2010](http://www.fool.com/investing/general/2010/08/04/apple-drops-skyhook-wireless-technology-from-iphon.aspx) since it’s own devices give them enough coverage not to need it. ---
**Author:** ![The\_Niply\_Elder](https://avatars.discourse-cdn.com/v4/letter/t/8e8cbc/32.png) [@The\_Niply\_Elder](https://boards.straightdope.com/u/The_Niply_Elder)\ **Post date:** [January 1, 2012, 7:36am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/26 "2012-01-01T07:36:26Z")
> [@Shalmanese](#): > > If your browser doesn’t ask you permission, it’s using GeoIP based on your IP address. If your browser is asking you permission, it’s based on a triangulation of the MAC addresses of nearby wireless routers. > > Historically, Skyhook wireless provided this service, more recently, Google has been building up their own database via Street View and currently, it’s largely being done via iOS phones (for Apple) and Android phones (for Google). You can occasionally see glitches in the system if someone moves a wireless router to a different location. Often, when I’m at an airport, my phone will think I’m at a completely different airport. Huh. Interesting. this explains the very annoying behavior of my android, as occasionally I want to use Google Navigation and I have to wait several minutes after it it establishes contact with GPS satellites for the correct location to be registered. This most frequently happens after I travelled a long distance (like after flying across the country) I normally leave the gps antenna off to save on battery, so I guess that the Google Nav initially relies on the crowd sourced location of 150 iPhones and Androids nearby, which when you land in a new location, they must all collectively refuse to believe they are at a new location, since they all agreed on the previous location. For instance, just two weeks ago I flew from Minneapolis to Indianapolis, picked up a rental, plugged in the destination to drive to (Kokomo) and it wasn’t until I drove halfway around the Indy wheelnspokes freeway that it decided to listen to the on board GPS hardware… Weird. Does anybody have problems like this? ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [January 1, 2012, 2:16pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/27 "2012-01-01T14:16:18Z")
> [@standingwave](#): > > It’s your user agent string. It contains your ISP and its location, your operating system, web browser, screen resolution/color depth and other stuff. Internet Explorer used to send the current contents of your clipboard until people started bellyaching about privacy. > > Go [here](http://www.spyber.com/) to see what it contains. > [@BorgHunter](#): > > This is untrue. Your user agent string contains your OS and browser + version, and that’s about it. The link you posted retrieves your location using IP address geolocation, and your screen resolution through JavaScript. When I went to that URL, it gave me the location I usually see, which is about 40 miles away from where I actually live. If I go to Google maps, it knows my zip code, and that’s it. That’s all I ever gave it to get directions somewhere, and I assume that’s in a cookie. So how do I see Google find my address? ETA: Wow! From that link, Internet Explorer will share your clipboard? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [January 1, 2012, 2:20pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/28 "2012-01-01T14:20:06Z")
> [@Shalmanese](#): > > Apple hasn’t used Skyhook since [2010](http://www.fool.com/investing/general/2010/08/04/apple-drops-skyhook-wireless-technology-from-iphon.aspx) since it’s own devices give them enough coverage not to need it. MAC, not Mac. ---
**Author:** ![JoelUpchurch](https://avatars.discourse-cdn.com/v4/letter/j/f05b48/32.png) [@JoelUpchurch](https://boards.straightdope.com/u/JoelUpchurch)\ **Post date:** [January 1, 2012, 5:16pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/29 "2012-01-01T17:16:56Z")
> [@ZenBeam](#): > > So how do I see Google find my address? www.google.com/latitude If you are on a desktop computer or not using Wifi, then it isn’t going to have much luck finding you. ---
**Author:** ![Shalmanese](https://avatars.discourse-cdn.com/v4/letter/s/45deac/32.png) [@Shalmanese](https://boards.straightdope.com/u/Shalmanese)\ **Post date:** [January 1, 2012, 6:41pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/30 "2012-01-01T18:41:56Z")
> [@beowulff](#): > > MAC, not Mac. I was replying to the parent comment that stated that their iPad used Skyhook. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [January 1, 2012, 7:39pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/31 "2012-01-01T19:39:00Z")
> [@JoelUpchurch](#): > > www.google.com/latitude > > If you are on a desktop computer or not using Wifi, then it isn’t going to have much luck finding you. Well, that asks me to share my location, and I’m not going to do that. So I don’t know if it knows where I am or not. ---
**Author:** ![yabob](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/yabob/32/2821_2.png) [@yabob](https://boards.straightdope.com/u/yabob)\ **Post date:** [January 1, 2012, 7:40pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/32 "2012-01-01T19:40:23Z")
What your browser sends - there are several “browser mirror” sites out there which will show you the headers sent by your browser are, and what it’s willing to tell sites about client side scripting / plugin support. Try this one: [http://centralops.net/asp/co/BrowserMirror.vbs.asp](http://centralops.net/asp/co/BrowserMirror.vbs.asp) The user agent strings sent by various browsers / web crawlers are very idiosyncratic in the sort of data that they send, and a lot of them don’t even adhere to the supposed standards for the data. It’s unlikely that it contains anything compromising. For instance, the browser I’m using as I type this sends “Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0.1) Gecko/20100101 Firefox/9.0.1”. You now know that I’m on Firefox 9.0.1 on a 64 bit Windows 7 system (Vista would be Windows NT 6.0 - Wow64 says that it is a 32 bit app running under the 32 bit emulation subsystem on a 64 bit machine). Or some other client which masquerading as such. Big deal. BTW, there’s a big database of user agent strings here: > **[UserAgentString.com - List of User Agent Strings](https://www.useragentstring.com/pages/useragentstring.php)** > > Understand what information is contained in a user agent string. Get an analysis of your or any other user agent string. Find lists of user agent strings from browsers, crawlers, spiders, bots, validators and others.. Location is from the IP address, as we have been discussing. TECHNICALLY, all that will give them is the ISP. In that browser mirror site, you may click on “what this reveals” next to your IP, and it will probably give you DNS record for a range assigned to your ISP. I said “technically”. As other posters have alluded to, many companies have attempted to provide “value added” information by correlating IP addresses with other sources of information in a variety of ways. With varying degrees of success. One of those links above tells me I’m sitting in Sanborn Skyline Park. Arguably, that might be more pleasant surroundings than my home office, but it isn’t terribly accurate. Sites that want to refer to my location variously say “San Jose”, “Cupertino” and “Saratoga”. Also keep in mind that most residential broadband is on dynamic DNS anymore - your IP will change every so often, rendering the data gathered by some of these outfits obsolete. ETA: NT 6.0 / 6.1 - in theory, those could indicate versions of Windows Server 2008 as well, but Vista / Windows 7 are far, far more likely. ---
**Author:** ![BigT](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bigt/32/12044_2.png) [@BigT](https://boards.straightdope.com/u/BigT)\ **Post date:** [January 3, 2012, 12:43am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/33 "2012-01-03T00:43:05Z")
Even with modern User Agent strings that try to obscure your identity, there are still ways to fingerprint you. For some stupid reason, every plugin you have is available in a JavaScript array. Flash and Java both have access to every font you have installed. This is often enough information to fingerprint you. There’s a way to shut off the sharing of a lot of that info, but, since so few people do that, that’s often enough to identify you. Test out [this website](http://panopticlick.eff.org/) to see if your browser is “unique”. From there, all you have to do is enter in your exact location into some website that is willing to fingerprint you and share (or sell) information, and, boom, they know where you are, who you are, and any other information. This is why I am still pressing for browsers to stop revealing this crap. Unfortunately, a few website (most notably Google Chat) rely on the feature. It would be easy to fix, but they don’t. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [January 3, 2012, 2:20am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/34 "2012-01-03T02:20:41Z")
Interesting. From my report: > [@](#): > > Your browser fingerprint appears to be unique among the 1,909,887 tested so far. > > Currently, we estimate that your browser has a fingerprint that conveys at least 20.87 bits of identifying information. But I notice that 20.87 bits is from my browser plugins, and those can and do change. My browser version and OS versions also change from time to time. So I’d think this information would become stale. I’m not sure how you’d track this as it changed. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [January 3, 2012, 2:33am UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/35 "2012-01-03T02:33:23Z")
OK, the 20.87 bits is probably from the number tested so far. My plugins had reported 20.87+, probably for the same reason. When I changed my plugins, the results for those changed to 17.x, but the total for my browser was still "at least 20.87 bits. ---
**Author:** ![londono](https://avatars.discourse-cdn.com/v4/letter/l/898d66/32.png) [@londono](https://boards.straightdope.com/u/londono)\ **Post date:** [January 4, 2012, 8:50pm UTC](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955/36 "2012-01-04T20:50:11Z")
> [@ZipperJJ](#): > > Yeah it’s your IP address. That’s all it is. It won’t get down to your actual home address but it will be able to identify either your town or a nearby town. > > [http://www.ipaddresslocation.org/](http://www.ip-address-lookup-v4.com) I’m pretty sure the OP is referring to the “My Location” option inside [maps.google.com](http://maps.google.com) which does not use the IP, but some other triangulation method to fetch your location [Previous page](https://boards.straightdope.com/t/how-does-my-pcs-web-browser-know-my-location/607955.md?page=1)