Why you might want to clear your cache and cookies

Cache is the temporary storage Firefox uses to load websites faster — it saves images, scripts, and other files so the browser doesn't have to read them again. Cookies are small text files that websites store on your computer to remember things about you: login information, what's in your shopping cart, your preferences. Clearing both removes that stored data.

You might clear them if a website isn't loading correctly, if you want to remove your browsing history before someone else uses your computer, or if you're concerned about tracking. Some people clear them regularly; others only when something breaks. Firefox lets you clear just one, both, or neither — and you can set it to clear automatically when you close the browser.

Key Takeaways

  • Open Firefox, press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac), and the Clear Recent History window opens when ready.
  • Set the time range to "Everything" if you want to clear all cache and cookies, or pick a specific time period like "Last Hour" or "Last 24 Hours".
  • Check the boxes next to "Cookies" and "Cache" to clear both, then click "Clear Now".
  • You can set Firefox to clear cache and cookies automatically every time you close the browser by going to Settings > Privacy & Security > History.

The fastest way: keyboard shortcut

Press Ctrl+Shift+Delete on Windows or Command+Shift+Delete on Mac. The Clear Recent History window opens when ready. This is the quickest route if you know you want to clear right now.

If the keyboard shortcut doesn't work, your Firefox version may be older. Use the menu method instead.

Using the Firefox menu

Click the hamburger menu (three horizontal lines) in the top right corner of Firefox. Scroll down and click "Settings". On the left side, click "Privacy & Security". Under the "Cookies and Site Data" section, click "Clear Data".

A smaller window appears with two checkboxes: "Cookies and Site Data" and "Cached Web Content". Check both boxes, then click "Clear". Firefox clears them when ready and closes the window.

Choosing what time period to clear

When you use the keyboard shortcut (Ctrl+Shift+Delete), a dropdown menu appears at the top labeled "Time range for clearing". By default it says "Everything", which clears all your cache and cookies from the entire history of that Firefox profile.

You can change it to "Last Hour", "Last 24 Hours", "Last 7 Days", "Last 4 Weeks", or "Everything". Pick the time period that matches what you need. If a website broke in the last few hours, clearing just the last hour's cache might fix it without removing login information from weeks ago.

Clearing cache and cookies automatically

If you want Firefox to clear cache and cookies every time you close the browser, go to Settings > Privacy & Security. Under "History", find the dropdown that says "Firefox will" and select "Use custom settings for history".

Check the box that says "Clear history when Firefox closes". Below that, click "Settings" and a new window opens. Check "Cookies" and "Cache" (and any other data you want cleared), then click "OK". From now on, Firefox clears those items when you close it completely — not when you close a single tab or window, but when you shut down the entire browser.

What gets cleared and what doesn't

Clearing cache removes temporary files Firefox downloaded to speed up websites. Clearing cookies removes login sessions, preferences, and tracking data that websites stored. If you clear both, you'll be logged out of most websites the next time you visit them.

Clearing cache and cookies does not delete your browsing history (the list of websites you visited). It does not delete bookmarks, saved passwords, or autofill information — those are stored separately. If you want to delete your browsing history too, check the "History" checkbox in the Clear Recent History window.

Troubleshooting if clearing doesn't fix the problem

If a website still doesn't load correctly after clearing cache and cookies, try closing Firefox completely and opening it again. Sometimes a website's server has a problem, not your browser. Wait a few minutes and try the website again.

If the problem persists, try opening the website in a private window (Ctrl+Shift+P on Windows, Command+Shift+P on Mac). Private windows don't use stored cache or cookies, so they load websites fresh. If the website works in private mode but not in normal mode, the problem is likely old cached data or a cookie conflict — clearing again and restarting Firefox usually solves it.

Frequently Asked Questions

Will clearing cache and cookies log me out of everything?

Yes, clearing cookies logs you out of most websites because cookies store your login session. You'll need to log back in the next time you visit. Cache clearing doesn't directly log you out, but it removes temporary files. If you want to stay logged in, clear only cache, not cookies.

Can I clear cache and cookies for just one website?

Firefox doesn't have a built-in way to clear cache and cookies for a single website. You can clear all of them, or clear by time period. If you need to remove data for one site only, use a private window for that site going forward, or clear everything and log back into the sites you use regularly.

What's the difference between clearing cache and clearing cookies?

Cache is temporary files (images, scripts, videos) that make websites load faster. Cookies are small text files websites use to remember you. Clearing cache speeds up your browser and frees up disk space. Clearing cookies removes login sessions and tracking data. You can clear one without the other.

Does clearing cache and cookies delete my passwords?

No. Passwords are stored separately in Firefox's password manager. Clearing cache and cookies does not affect saved passwords. If you want to delete a saved password, go to Settings > Privacy & Security > Logins and Passwords and remove it from the list.

Why does Firefox keep asking me to log in after I clear cookies?

Because cookies store your login session. When you clear cookies, Firefox removes that session information, so websites don't recognize you anymore. This is normal. Log in again, and Firefox will store a new cookie. If you don't want to clear cookies, clear only cache instead.