Why and when to clear your Firefox cache
Cache is a folder where Firefox stores copies of web pages, images, and files you have visited. When you return to a site, Firefox loads these copies from your computer instead of downloading them again, which makes pages load faster. Over time, cache takes up disk space and can sometimes cause a page to display an outdated version of itself.
You should clear your cache if a website looks broken or won't load properly, if you are using a shared computer and want to remove traces of where you have been, or straightforward to free up storage space. Firefox lets you delete cache on demand or set it to clear automatically every time you close the browser.
Key Takeaways
- Open Firefox settings, go to Privacy & Security, scroll to Cookies and Site Data, and click Clear Data to delete cache when ready.
- You can choose to clear only cache from the last hour, day, week, or all time — the default is everything.
- To clear cache automatically when you close Firefox, check the box for "Delete cookies and site data when Firefox is closed" in the same Privacy & Security section.
- Clearing cache does not delete your passwords, bookmarks, or browsing history unless you specifically select those options too.
- If a website still does not work after clearing cache, try opening it in a private window or disabling extensions.
How to clear cache right now in Firefox
The fastest way to delete cache is through the keyboard shortcut. Press Ctrl + Shift + Delete on Windows or Linux, or Command + Shift + Delete on Mac. This opens the Clear Recent History window directly.
If the shortcut does not work, 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 appear with checkboxes for what to delete.
By default, Firefox selects both Cookies and Site Data and Cache. The time range is set to Everything, which deletes all cache. If you only want to clear cache from today, click the dropdown that says Everything and choose Last Hour, Last 24 Hours, Last 7 Days, Last 4 Weeks, or Last 90 Days. Then click Clear.
The difference between cache and cookies
Cache and cookies are related but separate. Cache stores the actual files — images, stylesheets, videos — that make up a website. Cookies store small pieces of information like login status, preferences, or tracking data. When you clear data in Firefox, you can delete them together or separately.
If you only want to delete cache and keep yourself logged into websites, uncheck the Cookies and Site Data box before clicking Clear. If you want to delete cookies but keep cache, uncheck Cache Web Content instead. Most people clear both at once, which is the default.
Setting Firefox to clear cache automatically
To make Firefox delete cache every time you close the browser, go to Settings and click Privacy & Security. Under Cookies and Site Data, check the box that says Delete cookies and site data when Firefox is closed. From that point forward, your cache will clear automatically without you having to do anything.
This setting does not affect your bookmarks, passwords, or browsing history — those stay unless you delete them separately. If you want to keep yourself logged into certain websites even after closing Firefox, click the Manage Exceptions button next to that checkbox and add those sites to the list. Firefox will then keep cookies for those sites but delete everything else.
What gets deleted and what stays
When you clear cache in Firefox, you remove temporary copies of web pages and images. Your bookmarks, saved passwords, and browsing history remain unless you specifically check those boxes in the Clear Recent History window. Extensions and settings stay in place.
If you want to delete more than just cache — for example, to remove your browsing history or saved form data — the Clear Recent History window has checkboxes for each type of data. You can choose exactly what to remove. The default selection includes only cache and cookies, so you have to actively select history or passwords if you want those deleted too.
Troubleshooting when clearing cache does not fix the problem
If a website still displays incorrectly or fails to load after you clear cache, try opening it in a private window. Press Ctrl + Shift + P on Windows or Linux, or Command + Shift + P on Mac. A private window does not use cache at all, so if the site works there, cache was the problem and you may need to clear it again.
If the site still does not work in a private window, the issue is likely not cache. Try disabling extensions that might interfere with the site — click the menu button, go to Add-ons and Themes, find the extension, and toggle it off. You can also try a hard refresh by pressing Ctrl + F5 on Windows or Linux, or Command + Shift + R on Mac, which forces Firefox to read a fresh copy of the page instead of using cache.
How much space cache actually uses
Firefox does not display how much space cache is taking up before you delete it. The amount varies widely depending on how many sites you visit and how long you have been using Firefox. For most people, cache uses between 100 megabytes and 1 gigabyte. If your computer is running low on storage, clearing cache can free up some space, though it is usually not the biggest space hog on your system.
If you want to limit how much space Firefox can use for cache, go to Settings, click Privacy & Security, and scroll to Cookies and Site Data. Click Manage Data to see a list of sites and how much space each one uses. You can delete cache for individual sites without clearing everything, which is useful if one site is storing an unusually large amount of data.
Frequently Asked Questions
Will clearing cache delete my passwords?
No. Passwords are stored separately from cache. When you clear cache in Firefox, passwords stay saved unless you specifically check the box for Logins and Passwords in the Clear Recent History window. By default, that box is unchecked.
Can I clear cache for just one website?
Yes. In the Cookies and Site Data section of Privacy & Security settings, click Manage Data. Search for the website name, select it, and click Remove Selected. This deletes cache only for that site, leaving cache from other sites intact.
What is the difference between clearing cache and clearing browsing history?
Cache stores temporary files that make websites load faster. Browsing history is the list of websites you have visited. Clearing cache does not erase the history list, and clearing history does not remove cached files. You can delete either one separately or both together.
Does clearing cache log me out of websites?
Clearing cache alone does not log you out. Logging out requires deleting cookies, which are separate from cache. If you clear both cache and cookies together, you will be logged out of most websites. If you clear only cache, you should stay logged in.
How often should I clear my cache?
There is no set schedule. Clear cache when a website looks broken, when you want to free up space, or when you are using a shared computer. If you prefer not to think about it, set Firefox to clear cache automatically when you close the browser.