How-To Geek

How to Change Your Browser’s User Agent Without Installing Any Extensions


All popular browsers offer build-in user agent switchers, so you can change your user agent without installing any extensions. Google Chrome and Internet Explorer both include user agent switchers in their developer tools, while Firefox offers an about:config option.

Websites identify browsers by their user agents. Modify a browser’s user agent and it will appear as a different browser – or even a browser running on another device, such as a smartphone or tablet.

Google Chrome

Chrome 17 added a built-in user agent switcher. Previously, you had to modify Chrome’s command-line options to change its user agent.

The user agent switcher is part of Chrome’s Developer Tools – open them by clicking the wrench, pointing to Tools, and selecting Developer tools. You can also use the Ctrl-Shift-I keyboard shortcut.


Click the gear icon at the bottom right corner of the Developer Tools window to open the Settings pane.


From the Settings pane, enable the Override User Agent option under Network and select a user agent from the list. You can also select Other and enter your own, custom user agent.


This setting is temporary and only persists while you have the Developer Tools window open. Close the window and Chrome will revert to its default user agent.

Internet Explorer

Internet Explorer also has a user agent option in its developer tools. To open them, press F12 or select the F12 developer tools option from Internet Explorer’s Tools menu.


The developer tools will open in a separate pane at the bottom of the window. Click the Tools menu in the developer tools pane, point to “Change user agent string”, and select a user agent from the list.


You can also select the Custom option and add custom user agent strings to the list.


This setting is also temporary. Internet Explorer reverts to its default user agent after it’s closed.

Mozilla Firefox

Mozilla Firefox doesn’t have an easy way to change its user agent without an extension – this option is buried on Firefox’s about:config page. If you want an easy way to change Firefox’s user agent, use the User Agent Switcher extension instead.

To access the about:config page, type about:config into Firefox’s address bar and press Enter. You’ll see a warning – be careful when you change settings here, you could mess up Firefox’s settings.


Type useragent into the filter box. We’re looking for the general.useragent.override preference, but it probably won’t exist on your system.


To create the preference, right-click on the about:config page, point to New, and select String.


Name the preference general.useragent.override


Enter your desired user agent as the value of the preference. You’ll have to look up your desired user agent on the web and enter it exactly. For example, the following user agent is used by Googlebot, Google’s web crawler:

Mozilla/5.0 (compatible; Googlebot/2.1; +


This setting persists until you change it – even if you close and reopen Firefox. To revert Firefox to the default user agent, right-click the general.useragent.override preference and select Reset.


Safari also has a built-in user agent switcher. Check out our guide to changing your user agent on Safari for more information.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 05/8/12

Comments (12)

  1. Ko0lHaNDLuKe

    Thanks for this, interesting article. I had to change my user agent last year in order to fool an online test into thinking I was either using a really old version of Internet Explorer or (I could hardly believe it) Netscape! This was in order to practice for an online exam I had to do as part of a job interview. Fortunately the actual exam I was required to take was more up-to-date!
    Was a major pain in my arse (yes, I’m British)…

  2. Citrus Rain

    Now, the trick is to make the website work when mixing and matching user agents with rendering engines. (I have to change both the browser and document mode to match when I’m at work, or else it’s a mess)

  3. rice krispis

    Thanks, Chris. Most useful article to me.

  4. Dale

    How do you do it on an Android browser? The bane of my life is websites throwing me into “mobile mode” when I’m using a tablet.

  5. Andrew

    That’s cool. I didn’t know that I can change the useragent in chrome and IE.The settings for firefox is a little complicated.
    I have a tri-core avant browser, in the past if I want to change useragent, I change the rendering engine directly. This also works, but less of choices, Only have four opitions (IE7.ie7, firefox, chrome) available.
    Now , with the build-in user agent switchers, I have more choices.

  6. Jim

    I’d benefit from a small description of what a User Agent is and what is does – suggestion for future articles.

    I’m been trying to insert a new SEARCH Engine into MSIE9 and Chrome without success unless they are listed as an extension (in MSIE). They don’t seem to offer a way to insert a new search engine that can be made the DEFAULT.

    How about an article on this? I’d like to insert one of your recommended privacy browsers like IXQUICK.

  7. Chris Hoffman


    Thanks — some good post ideas.

    In Chrome, you should be able to right-click the address bar, select Edit Search Engines, and set any search engine you’ve used recently as your default. Not sure about IE — will have to investigate.

  8. bollocks

    I just read the definition from Wikipedia, and I still don’t understand it.

  9. DW

    I just followed the section for IE and I didn’t get a pane at the bottom of the window but a new window appeard and in the “Tools” menu I only had resize, ruler & color picker. Whats up with that? (using ie 8 on xp)

  10. lilsting10

    How would I go about tricking my desktop firefox into thinking it’s firefox mobile?

    I love the mobile versions of sites as they allow me to enlarge text – and when it gets too big for the horizontal frame it pushes text onto the next line rather than making me scroll left and right. I’d like to use these on my desktop pcs.

  11. Easy delete

    @Jim, @bollocks
    I think the term “user agent” is a bit confusing. See if this helps:

    A website takes your request for webpages and wants to serve data onto your computer screen in the best display for your computer..
    Your computer and software have certain features that may be unique and which could show a less than optimal display. So the website needs to know a bit about your computer setup.

    Your browser (when it requests the page you are visiting), sends to the website a small string of data to help the website decide what data to send back to you, most usually for the best display of the page by your particular browser onto your particular computer. That small string of data is the “user agent” description.

    The article does also describe some other ways in which the user agent description is used. E.g. traffic monitors can use it to tell how many computers are using Mac, or Windows, or Linux, or Chrome.

    Hope that helps.

  12. Chris Hoffman


    I believe this requires IE9 — sorry! You can always use another browser.

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