Private browsing clears local traces, not identity. Here is what incognito does, what it leaves untouched, and why your fingerprint is unaffected either way.
On this page
Does incognito mode hide you from the websites you visit?
No — and the distance between that answer and what people expect is where the disappointment lives. Private browsing has the strongest reputation of any privacy feature and the weakest grip on the thing people imagine it protects. The name encourages a picture of invisibility. What it actually delivers is a clean slate on your own device, and nothing at all beyond it. Knowing precisely where that line falls is useful, because the gap between the promise and the mechanism is where most of the misunderstanding sits.
What private mode does clear
Everything here is local: it concerns what your browser leaves on your machine, not what the network sees.
- Cookies and site data. A private window gets its own temporary store, separate from your normal profile, and those cookies are discarded when the last private window closes.
- History and form data. Pages you visit privately are not written into your browsing history, and text you type into forms is not offered back to you later.
- Local storage and similar stores.
localStorage,sessionStorageand IndexedDB are partitioned into the private session and cleared with it — the same family of storage discussed in local storage, IndexedDB and evercookies. - Cache and site permissions. Temporary files and any permissions you grant during the session are discarded rather than remembered.
If your goal is “do not leave traces on this computer”, private mode does that job well.
What it leaves untouched
Nothing about your connection changes when you open a private window.
Your IP address is identical. Your internet provider sees the same traffic. Your DNS lookups travel the same path, your network-level characteristics are unchanged, and any site you visit sees the same visitor arriving from the same place. If you are logged into an account, the site knows it. If your employer or school monitors the network, it still does.
Incognito is a local hygiene tool. It is not an anonymity tool, and treating it as one is the most common misunderstanding around it.
How detection checks work
Because private mode leaves the connection alone, sites have long tried to detect the mode itself — often to refuse access, sometimes simply to measure. The classic checks exploit the fact that a private session can behave slightly differently from a normal one.
The best known is a storage test. A page checks whether cookies are enabled, which reports true, then tries to write a cookie and read it straight back. In older versions of Chrome’s private mode, the write would silently fail while the setting still claimed cookies were on. The mismatch was the tell. You can see the first half of that test on the cookies enabled test.
A related check looks at storage quotas. Private sessions have historically been allocated different limits, or denied certain APIs altogether — the FileSystem API and some quota estimates have both been used this way. Asking navigator.storage.estimate() and comparing the answer with what a normal window returns can reveal which mode you are in.
The honest update is that these tests have become less reliable. Browsers have worked to close the differences, precisely because being detectable in private mode undermines the point of it. Detection still succeeds sometimes, but it is no longer the dependable signal it once was, and a site that blocks you for using private mode is often guessing.
Why fingerprinting is unaffected
This part follows directly from the sections above. A fingerprint is computed from your browser and device, not from what your browser has stored. Private mode changes what is stored. It does not change the screen you are reading this on, the graphics rendering, the installed fonts, the time zone or the platform.
So a site that fingerprints you recognises you in a private window exactly as it would in a normal one — before you have accepted a cookie, before any storage has been written, before anything the mode clears has had a chance to exist. Clearing your history does not disturb a signal that was never drawn from history in the first place.
That is also why private mode does not break cross-session tracking. A tracker that cannot set a cookie can still recognise the browser when it returns, and can then tie the new session to the old profile.
| Signal | Cleared by private mode | Unchanged |
|---|---|---|
| Cookies and site storage | Yes | |
| Browsing history | Yes | |
| IP address | Yes | |
| Browser fingerprint | Yes | |
| Network-level characteristics | Yes |
What it is genuinely good for
None of this makes private mode pointless; it is the right tool for a specific set of jobs.
- Borrowed computers. Signing into an account on a shared machine leaves far less behind in a private window.
- Price and content checks. A session without your usual cookies is a cleaner test of what a site shows a fresh visitor.
- Keeping one-off searches out of your history. Autocomplete and history suggestions are a real privacy surface, and private mode removes them.
What it cannot do is hide you from the site you are visiting. For that you need to address the connection — a different network, or a proxy that changes your apparent address — and to reduce how distinctive your browser looks. Those are separate problems requiring separate tools.
What would change this conclusion
The answer above rests on a single mechanism: private mode changes what your browser stores and leaves everything it sends untouched. If that ever stopped being true — if a private window changed what a site could see rather than only what your machine kept — the answer would change with it. Chasing that possibility is exactly what testing is for.
Open your browser’s private mode and run the incognito detection test inside it to see whether your session is distinguishable from a normal one. Then run the fingerprint test in both windows and compare the results. If the two are close, you have seen the boundary of what private browsing protects for yourself.