What clearing cookies does and why you might want to

Clearing cookies removes small files that websites store on your computer to remember information about you — login details, preferences, browsing history, and tracking data. When you clear them, websites will no longer recognize you when you return, and you will have to log back in to accounts. Clearing cookies can speed up Firefox if you have accumulated thousands of them, and it stops advertisers from tracking your movement across websites.

You do not need to clear cookies regularly unless you share your computer with others, use public WiFi often, or want to stop being tracked. If you clear them and then realize you need to stay logged into a site, you can always log back in — nothing is permanently deleted from the website itself.

Key Takeaways

  • Firefox stores cookies in a folder on your hard drive, and clearing them removes those files but does not affect your saved passwords or bookmarks.
  • You can clear all cookies at once through Firefox settings, or clear cookies from a single website by right-clicking on it.
  • Setting Firefox to clear cookies automatically when you close the browser prevents them from building up over time.
  • Clearing cookies will log you out of most websites, so you will need to log back in the next time you visit.

Clear all cookies at once through Firefox settings

Open Firefox and click the menu button (three horizontal lines) in the top right corner. Select Settings, then click Privacy & Security in the left sidebar. Scroll down to the Cookies and Site Data section and click the Clear Data button.

A window will pop up with two checkboxes. Make sure Cookies and Site Data is checked (it usually is by default). You can also check Cached Web Content if you want to free up disk space — this removes temporary files websites store to load faster next time. Leave Browsing & Download History unchecked unless you also want to clear your history. Click Clear and Firefox will delete the files immediately.

Clear cookies from just one website

If you only want to clear cookies from a specific site without affecting others, right-click anywhere on that website's page. Select Inspect from the menu (this opens Firefox's developer tools). Click the Storage tab at the top of the developer tools panel.

On the left side, expand Cookies by clicking the arrow next to it. You will see a list of websites. Click the one you want to clear, then right-click on any cookie listed and select Delete All. Close the developer tools by pressing F12 or clicking the X button, and the cookies from that site are gone. You will need to log back in the next time you visit.

Set Firefox to clear cookies automatically when you close it

Open Firefox and click the menu button (three horizontal lines) in the top right corner. Select Settings, then click Privacy & Security. Under the History section, find the dropdown that says Firefox will and select Use custom settings for history if it is not already selected.

Check the box next to Clear history when Firefox closes. A new set of options will appear below it. Click Settings next to that checkbox. A window will open showing what gets cleared. Make sure Cookies is checked, then click OK. From now on, Firefox will delete all cookies every time you close the browser completely — not just when you close a tab.

Understand the difference between clearing cookies and other data

Cookies are separate from your saved passwords, bookmarks, and browsing history. Clearing cookies will not delete any of those. Your saved passwords stay in Firefox's password manager unless you specifically clear them. Bookmarks remain in your bookmarks folder. Browsing history (the list of sites you have visited) stays unless you check that box when clearing data.

If you want to clear only cookies and leave everything else untouched, make sure you uncheck Browsing & Download History and any other boxes when you clear data. This gives you control over what actually gets removed.

What to do if you cannot find the Clear Data button

If you are using an older version of Firefox, the settings layout may be slightly different. Click the menu button and select Preferences instead of Settings. Then click Privacy instead of Privacy & Security. The Cookies and Site Data section should still be there with a Clear Data button.

If you still cannot find it, update Firefox to the latest version. Click the menu button, select Help, then About Firefox. Firefox will check for updates automatically and install them if available. After updating, the settings should match the steps above.

Frequently Asked Questions

Will clearing cookies delete my saved passwords?

No. Cookies and passwords are stored separately in Firefox. Clearing cookies will not affect your saved passwords, and you will still be able to log into sites that have your password saved. You would need to specifically clear passwords through the password manager to remove those.

Why am I still logged into websites after clearing cookies?

Some websites use other methods besides cookies to keep you logged in, such as tokens stored in browser storage or local storage. Right-click on the page, select Inspect, click Storage, and expand Local Storage and Session Storage to clear those as well. You can also clear all site data at once by checking Cookies and Site Data in the Clear Data window.

Does clearing cookies speed up Firefox?

It can, but usually only if you have been using Firefox for years without clearing cookies. If Firefox feels slow, clearing cookies might help slightly, but restarting Firefox or closing unused tabs usually makes a bigger difference. Clearing cookies is more useful for privacy than for speed.

Can I clear cookies from only the last hour or day?

Yes. In the Clear Data window, look for a dropdown at the top that says Time range to clear. Click it and select Last Hour, Last 2 Hours, Last 4 Hours, Today, or Everything. This lets you clear only recent cookies while keeping older ones.