Clearing cookies in Firefox removes tracking data that websites store on your computer
When you visit a website, it can store small files called cookies on your computer. These files remember things like your login information, what you put in your shopping cart, and which ads you've seen. Some cookies are useful — they let you stay logged in or remember your preferences. Others track your behavior across many websites and sell that information to data brokers and advertisers.
Clearing your cookies regularly breaks some of those tracking chains. It won't stop all data collection — your internet provider and the websites themselves still see what you do — but it removes one layer of the trail that follows you around the web. If you arrived here from the data broker guide, clearing cookies is one step in limiting what information brokers can collect about you in the first place.
Firefox stores your cookies in a central location and gives you several ways to delete them: all at once, by website, or automatically when you close the browser.
Key Takeaways
- Open Firefox, press Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac), and you'll see the Clear Recent History window where you can delete all cookies at once.
- Set Firefox to clear cookies automatically every time you close the browser by going to Settings, Privacy & Security, and choosing "Delete cookies and site data when Firefox is closed."
- You can delete cookies from a single website by clicking the lock icon next to the web address, then clicking the arrow next to "Connection find," then "Clear Cookies."
- Clearing cookies will log you out of most websites, so you'll need to sign back in the next time you visit them.
- Cookies are different from your browsing history — clearing one does not clear the other, though you can clear both at the same time.
Clear all cookies at once using the keyboard shortcut
The fastest way to delete all your cookies is to use Firefox's keyboard shortcut. Press Ctrl+Shift+Delete on Windows or Command+Shift+Delete on Mac. A window titled "Clear Recent History" will open.
At the top of that window, you'll see a dropdown menu that says "Time range to clear." Click it and choose how far back you want to go. "Everything" deletes all cookies Firefox has stored. "Last Hour," "Last 2 Hours," "Last 24 Hours," and "Last 7 Days" delete only cookies from that time period.
Below that, make sure the checkbox next to "Cookies" is checked. You'll see other options like "Browsing & read History," "Cache," and "Site Preferences" — leave those unchecked unless you want to delete those too. Then click the blue "Clear Now" button. Firefox will delete the cookies and close the window.
Delete cookies automatically when you close Firefox
If you want Firefox to clear your cookies every time you close the browser, you can set that up once and then forget about it. Click the menu button (three horizontal lines) in the top right corner of Firefox, then click Settings.
On the left side of the Settings page, click Privacy & Security. Scroll down to the section labeled "Cookies and Site Data." You'll see a checkbox that says "Delete cookies and site data when Firefox is closed." Check that box.
Once you do this, Firefox will automatically clear all cookies the moment you close the browser completely — not just when you close a tab. The next time you open Firefox and visit a website you were logged into, you'll need to log in again. This is the trade-off: better privacy, but slightly more inconvenience.
Delete cookies from a single website
Sometimes you want to keep cookies from most websites but remove them from one specific site. Click the lock icon next to the web address in the address bar. A popup will appear showing connection information.
Click the arrow or chevron next to "Connection find" to expand that section. You'll see an option that says "Clear Cookies." Click it. Firefox will delete only the cookies that website stored, while leaving your cookies from other sites untouched.
This is useful if you want to log out of a website without logging out of everything else, or if you want to remove tracking cookies from a particular site while keeping cookies that help you stay logged in elsewhere.
Understand what clearing cookies does and does not do
Clearing cookies stops websites from using stored cookies to track you, and it prevents data brokers from buying cookie-based profiles about your browsing. But it is not a complete privacy solution. Your internet service provider can still see which websites you visit. The websites themselves still log your activity. And if you're logged into a Google, Facebook, or Microsoft account while you browse, those companies track you across the web regardless of cookies.
Clearing cookies also won't remove information that data brokers have already collected and sold. That's why the data broker guide recommends both clearing cookies going forward and requesting removal from broker websites separately — they are two different problems with two different solutions.
If you want stronger privacy protection beyond clearing cookies, consider using Firefox's built-in Enhanced Tracking Protection, which you can turn on in Settings under Privacy & Security. You can also use a VPN or the Tor Browser for additional anonymity, though those have their own trade-offs in terms of speed and convenience.
Know the difference between cookies, cache, and browsing history
Firefox stores three different types of data about your browsing, and they are not the same thing. Cookies are small files that websites store to remember information about you. Cache is a copy of images, scripts, and other files from websites that Firefox stores so pages load faster the next time you visit. Browsing history is the list of websites you've visited, which appears in your History menu.
When you clear cookies using the keyboard shortcut or the Settings menu, you can choose to clear any combination of these three. If you only check "Cookies," your browsing history and cache stay. If you check all three, Firefox deletes all of them. Most people clear cookies regularly but keep cache and history unless they have a specific reason not to — cache helps pages load faster, and history is useful for finding a website you visited before.
Frequently Asked Questions
Will clearing cookies log me out of websites?
Yes. Most websites use cookies to keep you logged in. When you clear cookies, Firefox deletes those login cookies, so you'll be logged out. The next time you visit that website, you'll need to enter your username and password again. This is why many people clear cookies on a schedule (weekly or monthly) rather than every single day.
Can I clear cookies from some websites but not others?
Yes. You can delete cookies from a single website by clicking the lock icon next to the address bar and selecting "Clear Cookies." You can also tell Firefox to never store cookies from certain websites by going to Settings, Privacy & Security, scrolling to "Cookies and Site Data," clicking "Manage Exceptions," and adding the website to the blocklist.
What if I clear cookies but still see ads following me around?
Cookies are only one way websites track you. Even after clearing cookies, advertisers can track you through your IP address, your device fingerprint, or by logging into your Google or Facebook account. Clearing cookies helps, but it is not a complete solution. For stronger protection, enable Enhanced Tracking Protection in Firefox Settings or consider using a VPN.
Do I need to clear cookies if I use private browsing mode?
No. Firefox's private browsing mode (Ctrl+Shift+P on Windows, Command+Shift+P on Mac) does not store cookies at all — they are deleted automatically when you close the private window. If you do most of your browsing in private mode, you do not need to manually clear cookies from regular browsing as often.
Will clearing cookies delete my saved passwords?
No. Passwords are stored separately from cookies. When you clear cookies, your saved passwords stay in Firefox. If you want to delete saved passwords, you have to do that separately in Settings under Privacy & Security, in the "Logins and Passwords" section.