Chrome greets you with a cartoon spy in a trench coat when you open an Incognito window. It is a slightly misleading mascot. That little detective is very good at one job — hiding your browsing from the other people who use your computer — and essentially useless at the job most people assume he is doing, which is hiding your browsing from the internet.
This confusion is so widespread that it ended up in court. In 2024 Google settled a class-action lawsuit that accused it of tracking people even in Incognito mode, and the company rewrote the mode’s description to spell out the limits. The current text is worth quoting, because it is the clearest summary of what private browsing actually does: others you share your device with won’t see your activity, “but this does not change how the websites you visit and the services they use (including Google) collect data.”
So here is the honest breakdown — what disappears, what doesn’t, and where a private window is genuinely worth using.
Your device forgets. The internet remembers.
Private browsing — Incognito in Chrome, Private Window in Firefox, Private Browsing in Safari — is a local clean-up tool. The browser treats the session as a temporary one. When the session ends (when you close every private window), it throws away the traces it would normally keep. Everything else — the journey your data takes between your device and the website — is untouched.
Think of it less like invisibility and more like browsing on a library computer that someone else resets after you leave. Nobody who sits down next to you afterwards finds your traces. But the library’s network records still know someone visited those pages.
What actually disappears when you close the window
In Chrome’s Incognito mode, per Google’s own help pages:
- Browsing history — the pages you opened aren’t recorded in your history.
- Cookies and site data — new cookies are deleted after you close all Incognito windows, so sites won’t remember you the next day.
- Form data — information you typed into forms isn’t saved.
- Download history — the downloads aren’t listed in Chrome’s download history (though the files themselves stay on your device).
Firefox’s Private Browsing works the same way on the local side, and adds a couple of differences: private windows carry a purple mask so you can tell them apart, and Firefox’s tracking protection — which blocks known third-party trackers and cookies — is switched on by default there. If you’d like to understand what those cookies actually do before a private window throws them away, our explainer on what happens when you click “Accept All Cookies” covers them in plain terms.
A few things do survive a private session, by design: anything you download stays on the device, and any bookmarks you save stay in your bookmark list. If you download something you don’t want found, the private window can’t help you with that part.
The parties that can still see what you did
This is the part the trench-coat mascot glosses over. Private browsing protects you from exactly one observer: other people who use your device. It does not change who you are online.
The websites you visit can still see you. Your IP address is visible, and if you log in to anything, they know exactly whose account it is. Google’s own help text is blunt about this: websites identify you as a new user in Incognito, and won’t know who you are — “as long as you don’t sign in.”
Your internet service provider can still log the sites you visit, because it handles your connection. Browsing in a private window changes nothing about the request your router and ISP process.
Your employer or school can still monitor you if you’re on their network or device. If the computer or the network is theirs, their visibility into your traffic doesn’t depend on your browser’s history file.
Private browsing also offers no protection against malware, keyloggers, or phishing — Mozilla’s own help pages make this explicit. It’s designed to reduce traces on your own device, not to defend your device from attack.
Signing in inside a private window partly defeats the point
This is the trap most people walk into. You open an Incognito window and then sign in to Gmail, Facebook, or your bank — and from that moment, the signed-in site knows precisely who is browsing. Your history isn’t saved on your device, but the account holder’s activity is recorded on the company’s servers, the same as always. Google has said this directly: if you use Incognito while signed into your Google Account, your browsing activity will still be recorded by Google.
The rule of thumb: a private window starts you off looking like a stranger to websites. The moment you sign in, you’ve introduced yourself.
What private browsing is genuinely good for
None of this makes the feature pointless — it’s just a different tool than the one people imagine. It’s the right tool for:
- Shared or public computers. On a family PC, a hotel computer, or a library terminal, a private window means you leave no browsing history, no saved logins, and no form data behind.
- Surprise shopping. Google’s own example: shopping for a birthday gift on a shared device, without the purchase showing up in the browser history or triggering ads for it later on that device.
- Two accounts at once. Log into your work account in a normal window and your personal account in a private window at the same site — the private window has no access to your normal session’s cookies, so the two don’t collide.
- Seeing a site the way a stranger does. Web developers and curious readers use private windows to check how a website looks when nobody is logged in, without having to log out first.
- Diagnosing a browser problem. If a site misbehaves in your normal window but works in a private one, the cause is probably a cookie, cache, or extension — extensions are disabled in private windows by default, which narrows it down fast.
A few myths worth dropping
“It makes me anonymous.” No. Your IP address, your ISP, and any site you sign into can still identify you. Only tools like a VPN or Tor change that, and those are separate products with their own trade-offs.
“It protects me from viruses.” No. Private browsing does nothing to stop malware or phishing pages. Your browser’s security warnings still matter just as much.
“It lets me get around blocked sites.” Not by itself. If your school or workplace blocks a site at the network level, a private window hits the same block.
“It blocks ads.” Not exactly. Chrome blocks third-party cookies by default in Incognito now, which reduces some ad tracking — and Firefox runs its tracking protection there — but a private window is not an ad blocker.
How to open a private window
In Chrome, click the three-dot menu at the top right and choose New Incognito window, or press Ctrl + Shift + N on Windows, Linux, or ChromeOS, or ⌘ + Shift + N on a Mac. You can keep normal and Incognito windows open at the same time — just remember that all your Incognito windows share one session, which ends only when you close every one of them.
In Firefox, open the menu and choose New Private Window (or right-click any link and open it in one directly). Private windows get a darker theme and the purple mask so you can tell at a glance which kind of window you’re in. Safari offers the same Private mode on iPhones and Macs, and keeps its private tabs visually distinct so you don’t mix them up.
That’s the whole story. Private browsing is a good, honest feature that hides your tracks from the people sitting next to you — and a terrible feature for hiding them from anyone else. Used with that in mind, it’s one of the handiest shortcuts in the browser. Expected to do more, it will quietly let you down.
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