In browsers such as Chrome, a private window uses a temporary session within the existing profile. Guest mode starts a separate temporary profile without the host profile's saved logins and history. Availability and exact behavior vary by browser and device. The distinction matters on a shared computer.
Private window
Useful when the owner wants a temporary session. Bookmarks and some configured extensions may remain available, while temporary history and cookies are discarded when all private windows close.
Guest mode
Better when another person needs short-term access because it avoids exposing the owner's saved accounts and profile data. Downloads remain on the computer unless removed.
Shared limitations
Neither mode anonymizes a signed-in account or hides connection metadata from network operators. HTTPS still protects page content in transit; device-management software may have additional visibility. Files, bookmarks and information submitted online can persist outside browser history.
Choose by ownership
Use private browsing for your temporary session and guest mode for someone else's session on your device. For a public computer, avoid sensitive accounts entirely when a trusted personal device is available.
Downloads are the common surprise
Both modes can leave downloaded files on disk even when the browser removes the download list. On a shared device, remove files you downloaded and check the downloads folder and any synchronized copies. Closing the session does not erase those files or guarantee that deleted data cannot be recovered. Printing, screenshots and copied clipboard data also exist outside browser history.
For account recovery
A private or guest session may trigger extra security checks because saved device state is absent. Do not start a critical recovery flow on an unfamiliar public computer when a trusted device is available.