Incognito mode: what private browsing does and does not do
Incognito mode in Chrome and private windows in Firefox stop the browser keeping a record of your session on the computer you are using: no history, no cookies and no form entries once you close the window. They do not hide what you do from the websites you visit, from whoever runs the network, or from malware on the computer. Private browsing protects you from the next person at the keyboard, not from the internet.
This is the first of three short articles on browser privacy and security. The second covers choosing a privacy browser and the third ad blockers and browser extensions.
In short
- Incognito mode and private windows delete history, cookies, form entries and cached files from your own device when you close the window.
- Websites, your employer, your school, your internet provider and malware can all still see what you do.
- Private browsing suits shared computers, second accounts and keeping a search off the household history.
- For tracking across websites, ads and your network, you need a privacy browser, a content blocker and, on public Wi-Fi, a VPN.
What does incognito mode do?
It clears the session when you close the window. The browser throws away what the session left behind:
- the pages you visited (history)
- cookies and site data, so you are signed out of everything you signed in to
- what you typed into forms
- temporary files the browser cached
Google's Chrome help pages and Mozilla's Firefox support pages both describe this. Chrome also blocks third-party cookies by default in Incognito, which stops many advertising networks following you from site to site during that session.
Firefox goes a little further in private windows. Mozilla says it blocks known trackers, keeps each site's cookies in a separate jar, adds protection against fingerprinting (identifying a browser by its unique combination of settings) and sends the Global Privacy Control signal, which asks websites not to sell or share your data.
Does incognito mode make you anonymous?
No. Private browsing changes what is stored on your device, not what other people can see.
| Who | Can they still see what you do in a private window? |
|---|---|
| The next person using the computer | No. The history, cookies and form entries are gone. |
| The websites you visit | Yes. They see your IP address and what you do on their pages. If you sign in, they know who you are. |
| Your employer, school, hotel Wi-Fi or internet provider | Yes. They can see which sites you connect to. |
| Malware, keyloggers and phishing pages | Yes. Mozilla says private browsing does not protect against them, and a fake login page is as dangerous in a private window as anywhere else. |
Some things stay. In Firefox, bookmarks you add, passwords you choose to save and files you download remain after the window closes.
What did the Incognito settlement say?
In a class action in the United States, Brown v. Google, Google agreed in 2024 to settle claims about what it collected during Incognito sessions. Under the settlement as filed, Google is to change the wording it shows when Incognito opens, delete or deal with older private-browsing data, and keep third-party cookies blocked by default in Incognito for five years. Google supports approval of the settlement but disputes how the plaintiffs describe the facts. The court docket linked under Sources shows the current position.
The practical lesson is the one Google's own help page now gives: Incognito changes what is stored on your device, not what the sites you visit can see.
When is private browsing the right tool?
- On a computer you share, so the next user does not inherit your history or open sessions. Better still, avoid signing in to important accounts on a shared or public computer at all.
- To sign in to a second account without signing out of the first.
- To see a website as a stranger sees it, without your cookies, which is useful when checking your own site.
- To keep a gift or a medical search off the household history.
What should you use when you want more?
Private browsing deals with your own device. For the rest:
| You want to stop | Use | Where to read more |
|---|---|---|
| Tracking across websites | A browser with strong tracking protection on all the time | Part 2, choosing a privacy browser |
| Ads, trackers and malicious adverts | A content blocker you can trust, and few other extensions | Part 3, ad blockers and browser extensions |
| The local network seeing which sites you visit | A VPN. HTTPS, which almost every site now uses, already protects the content of what you send. | Noiz offers a managed VPN for desktops, laptops and phones |
| Malware | Updates, official software only, and care with downloads | Infostealer malware: how to protect your business passwords |
Read next:
- Choosing a privacy browser: Firefox, Brave, LibreWolf and Safari, part 2 of this series.
- Infostealer malware: how to protect your business passwords, on why malware makes private browsing irrelevant.
- Privacy-focused operating systems for phones and computers, on privacy below the browser.
If you work from public Wi-Fi often, a managed VPN from Noiz encrypts the connection from each of your devices.
Sources
- Google Chrome Help, browse in private (Incognito): https://support.google.com/chrome/answer/95464
- Google Chrome Help, third-party cookies in Incognito: https://support.google.com/chrome/answer/9845881
- Mozilla Support, private browsing in Firefox: https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history
- Mozilla Support, how private windows protect you: https://support.mozilla.org/en-US/kb/common-myths-about-private-browsing
- Brown v. Google LLC, docket and settlement filings (N.D. Cal.): https://www.courtlistener.com/docket/17216783/brown-v-google-llc/
- Global Privacy Control (W3C draft): https://www.w3.org/TR/gpc/
Note: while some of this content was produced with the help of AI, the final editing has been done by a real human being.
