How to change the locale in chrome browser

I want to change Accept-language request header to anything I wanted in chrome, is there any extension or plugin where I can do it. I want to be able to change locale and language both. Main requirement is changing the locale.

Open chrome, go to chrome://settings/languages

On the left, you should see a list of languages. Use mouse to drag the language you want to the top, that will change the order for the values in Accept-language of requests.

If you still don't see the language you prefer, it may be cookies. Go to cookies and clean it up you should be good.

Feb, 2022 Update:

On Chrome, press F12 to open Developer Tools:

Then, press Esc to open another panel which has Sensors tab:

Finally, you can set the Locale like "ja-JP" by choosing the Location, "Tokyo" as shown below:

If there isn't Sensors tab, you can open it from the 3 dots as shown below:

I use this function for testing internationally launched website.

Based from this thread, you need to bookmark chrome://settings/languages and then Drag and Drop the language to make it default. You have to click on the Display Google Chrome in this Language button and completely restart Chrome.

[on hold: broken in Chrome 72; reported to work in Chrome 71]

The "Quick Language Switcher" extension may help too: https://chrome.google.com/webstore/detail/quick-language-switcher/pmjbhfmaphnpbehdanbjphdcniaelfie

The Quick Language Switcher extension allows the user to supersede the locale the browser is currently using in favor of the value chosen through the extension.

Use ModHeader Chrome extension.

Or you can try more complex value like Accept-Language: en-US,en;q=0.9,ru;q=0.8,th;q=0.7

There is an article written by the devtools team describing how change the location settings in Chrome for testing purposes: https://developers.google.com/web/tools/chrome-devtools/device-mode/geolocation

The easiest way I found, summarized in a few pictures:

You could skip a few steps (up to step 4) by simply navigating to chrome://settings/languages right away.

To see what's your current locale, do

Intl.NumberFormat().resolvedOptions().locale

in Dev Tools > console. (more details)

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The top answer here is both outdated, and does NOT work in Mac OS (November 2021).

The official answer is available at: https://developer.chrome.com/docs/extensions/reference/i18n/#how-to-set-browsers-locale

Windows: Using the UI

Here's how to change the locale using the UI on Google Chrome for Windows:

• App icon > Options
• Choose the Under the Hood tab
• Scroll down to Web Content
• Click Change font and language settings
• Choose the Languages tab
• Use the drop down to set the Google Chrome language
• Restart Chrome

Mac OS X

To change the locale on Mac, you use the system preferences.

• From the Apple menu, choose System Preferences
• Under the Personal section, choose International
• Choose your language and location
• Restart Chrome

Linux

To change the locale on Linux, first quit Google Chrome. Then, all in one line, set the LANGUAGE environment variable and launch Google Chrome. For example:

LANGUAGE=es ./chrome

Chrome OS

To change the locale on Chrome OS:

• From the system tray, choose Settings.
• Under the Languages and input section, choose the Language dropdown.
• If your language is not listed, click Add languages and add it.
• Once added, click the the 3-dot More actions menu item next to your language and choose Display Chrome OS in this language.
• Click the Restart button that appears next to the set language to restart Chrome OS.