Private browsing is a browser feature for handling a session differently from ordinary browsing. It can be useful when you want a fresh sign-in context or want to limit certain records saved by the browser. The important first step is naming the privacy goal, because local browser history, account activity and network visibility are different questions.
Start with a specific goal
Suppose you want to view a website without using your usual signed-in account. A private window can provide a separate session for that task. Suppose instead you want the website, employer or network operator to have no information about the visit. Private browsing alone does not provide that outcome. The same feature can suit one goal and be insufficient for another.
Mozilla explicitly explains that Firefox private browsing does not make someone anonymous on the internet. Its documentation describes which browser records are handled differently and notes important exceptions. Read your own browser's current guidance, since private modes differ in implementation and may interact with other settings.
Separate local records from service records
A browser can choose not to retain certain local history while an online service still receives your requests. If you sign into an account, the service can associate activity with that account according to its operation and policies. Opening a private window does not erase the information already held by the service or change the content you voluntarily submit.
For example, using a private window to log into a shopping account still gives that service a signed-in session. The feature may help avoid using another person's existing login on the same device, but it does not make the order anonymous to the retailer. Decide whether the account is necessary for the task and understand what you are sending.
Review downloads and saved items
Downloaded files can remain on the computer after a private session closes. Bookmarks or other deliberately saved items may also persist according to the browser's behaviour. If you use a shared device to download a document, closing the window is not a cleanup plan for the document itself. Know where the file was saved and whether it should remain there.
Avoid using a borrowed or public computer for sensitive work when a trusted device is available. Private mode does not repair an untrusted operating system or make all installed software harmless. If you must use shared equipment, follow the service and location's supported guidance, sign out and handle any downloaded information deliberately.
Consider extensions and browser settings
Check which extensions are allowed to operate in private windows. A tool that is disabled may not provide the password-management or page-adjustment function you expect. A permitted tool may have access relevant to its permissions. Browser guidance should explain the available controls. Do not assume that private mode automatically removes every other component from the session.
Also distinguish a private window from a separate browser profile. A profile can support persistent separation between work and personal accounts, while private mode is often suited to a temporary session. Choose based on the task. Repeatedly rebuilding the same work environment in temporary windows may create inconvenience without addressing the privacy concern you originally had.
Test the intended behaviour
For a basic signed-out viewing test, open a private session and check that the service is not already authenticated. Then perform the task and close all relevant private windows when finished. Use the browser's current instructions for ending the session; closing one tab may not end other private windows still open.
If your concern is workplace monitoring, a specific threat or a sensitive service, seek guidance that addresses that actual situation. Avoid selecting tools from a vague promise of total privacy. Private browsing is most useful when its scope is understood: a different browser session with defined local behaviour, used alongside deliberate choices about devices, accounts and information.
Sources and further reading
This original guide was prepared with AI assistance. Examples are illustrative. The edition date is an assigned date in this 2026 catalogue. See our editorial policy and report a correction.