What clearing your cache does

Clearing your cache removes temporary files that Firefox has stored on your computer — images, scripts, and partial web pages that the browser saves to load websites faster the next time you visit them. Over time, this cache folder grows large and can slow down your browser or cause websites to display outdated versions of themselves.

When you clear the cache, Firefox deletes these stored files but keeps your passwords, bookmarks, and browsing history intact (unless you choose to delete those too). The next time you visit a website, Firefox will read fresh copies of everything, which takes a few seconds longer but ensures you see the current version.

Most people clear their cache when a website looks broken, loads slowly, or shows old content even after refreshing. It is also useful before selling or giving away your computer, or if you straightforward want to free up disk space.

Key Takeaways

  • Open Firefox, press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac), and the cache-clearing window opens when ready.
  • Select "Cached Web Content" from the list, choose your time range (usually "Everything"), and click "Clear Now".
  • Clearing cache does not delete your passwords, bookmarks, or browsing history unless you specifically check those boxes.
  • If a website looks broken or shows old content, clearing cache is often the fastest fix before contacting support.

The fastest way: keyboard shortcut

The quickest method is to use Firefox's keyboard shortcut. On Windows, press Ctrl+Shift+Delete. On Mac, press Command+Shift+Delete. The "Clear Recent History" window will open when ready.

At the top of this window, you will see a dropdown menu that says "Time range to clear". Click it and select "Everything" unless you only want to clear cache from the last hour or day. Then look at the list of checkboxes below — you should see "Cached Web Content" already checked. Leave it checked and uncheck anything else you want to keep (like "Cookies and Site Data" or "Browsing & read History").

Click the blue "Clear Now" button at the bottom right. Firefox will delete the cache files in a few seconds, and the window will close automatically.

The menu method if the shortcut does not work

If the keyboard shortcut does not open the window, you can reach the same tool through Firefox's menu. Click the three horizontal lines (the menu button) in the top right corner of Firefox. A dropdown menu appears.

Select "Settings" from this menu. On the left side of the Settings page, click "Privacy & Security". Scroll down until you see a section called "Cookies and Site Data". Below that, you will see a button that says "Clear Data" — click it.

The same "Clear Recent History" window opens. Follow the same steps as above: set the time range to "Everything", make sure "Cached Web Content" is checked, and click "Clear Now".

What to do if you want to clear cache automatically

If you clear your cache regularly, you can set Firefox to do it automatically every time you close the browser. Open Firefox's menu (three horizontal lines, top right) and go to "Settings". Click "Privacy & Security" on the left.

Under the "Cookies and Site Data" section, you will see a checkbox that says "Delete cookies and site data when Firefox is closed". Check this box. Firefox will now clear cache, cookies, and site data every time you close the browser completely.

Be aware that this also clears cookies, which means websites will forget you were logged in. You will have to log back in to email, social media, and other accounts the next time you visit them. If that is too inconvenient, stick with clearing cache manually when you notice a problem.

When clearing cache actually solves the problem

Clearing cache fixes issues where a website displays incorrectly, loads slowly, or shows outdated information. If you see a broken layout, missing images, or a page that says "sold out" when you know items are in stock, cache is often the culprit. Refresh the page first (press F5 or Ctrl+R), then clear cache if the refresh does not help.

Cache problems are less common than they used to be because modern websites are better at telling browsers when content has changed. But they still happen, especially on older websites or when a site updates its design. Clearing cache is always worth trying before you assume something is broken.

If clearing cache does not fix the problem, the issue is likely something else — a problem with your internet connection, an issue with the website itself, or a browser extension interfering with the page. Try opening the website in a different browser to narrow down the cause.

The difference between cache, cookies, and browsing history

These three things are separate, and Firefox lets you clear them independently. Cache is temporary files (images, scripts, stylesheets) that help pages load faster. Cookies are small text files that websites use to remember you — they store login information, preferences, and tracking data. Browsing history is the list of websites you have visited, which Firefox displays in your history menu.

When you clear cache, cookies and history remain unless you check their boxes too. This is useful if you want to fix a broken website without logging out of everything. If you are selling your computer or want to erase all traces of your browsing, you would check all three boxes before clicking "Clear Now".

Frequently Asked Questions

Will clearing cache delete my passwords?

No. Passwords are stored separately from cache, cookies, and history. Even if you clear all three, your saved passwords remain in Firefox. If you want to delete passwords too, you would need to go to Settings > Privacy & Security > Logins and Passwords and manage them there.

How much space does cache usually take up?

Cache size varies depending on how much you browse and how long it has been since you last cleared it. For most people, cache takes up between 100 MB and 1 GB. If you are running low on disk space, clearing cache can free up some room, though it is usually not the biggest space hog on your computer.

Do I need to close Firefox before clearing cache?

No. You can clear cache while Firefox is open and running. The browser will continue to work normally. However, if you use the automatic clearing option (delete cache when Firefox closes), Firefox must be fully closed for it to take effect — straightforward minimizing the window does not trigger it.

What if clearing cache does not fix the website problem?

Try refreshing the page with Ctrl+F5 (Windows) or Command+Shift+R (Mac), which forces Firefox to read everything fresh instead of using cache. If that does not work, try opening the website in a different browser like Chrome or Edge. If it works in another browser, the problem is Firefox-specific and might be an extension or setting issue.

Is it safe to clear cache?

Yes, completely safe. Clearing cache only removes temporary files that Firefox can rebuild by downloading them again. It will not damage your browser, delete important files, or cause any problems. Websites will straightforward load a bit slower the first time you visit them after clearing cache.