Cookies are small files that websites store on your device to remember things about you
When you visit a website, the site can ask your browser to save a small text file called a cookie. That file sits on your computer or phone and contains information — usually just a few hundred bytes, like a username, a preference you set, or a tracking ID. The next time you visit that same website, your browser automatically sends the cookie back, and the site reads what's in it.
Cookies are not programs. They cannot run code, steal files, or infect your device. They are just text. But because they persist between visits and can track your movement across the web, they are one of the main ways websites and advertisers learn about your behavior.
Key Takeaways
- Cookies are text files that websites store on your device to remember information about you between visits.
- First-party cookies come from the website you are visiting; third-party cookies come from advertisers or analytics companies and track you across multiple sites.
- You can see what cookies a site has stored, delete them, and block new ones from being set — usually in your browser settings under Privacy or History.
- Blocking all cookies may break some websites, but blocking third-party cookies usually does not affect the site's core function.
- Cookie consent banners exist because laws in Europe, California, and other places require websites to tell you what they are tracking.
First-party cookies: what the website itself stores
A first-party cookie is set by the website you are actually visiting. When you log into Gmail, Google sets a cookie that contains your session ID — a token that proves you are logged in. When you add items to a shopping cart on Amazon, Amazon sets a cookie that remembers what is in your cart. When you change the text size on a news site, that preference gets stored in a cookie so the site looks the same the next time you visit.
These cookies are usually necessary for the site to work the way you expect. Without them, you would have to log in again every time you refreshed the page, your shopping cart would empty, and your preferences would vanish. Most people do not object to first-party cookies because they make the site more convenient.
Third-party cookies: tracking across websites
A third-party cookie is set by a company other than the one running the website you are on. The most common example is an advertising network. When you visit a news site, that site may embed an ad from Google's ad network. Google sets a cookie on your device that tracks the fact that you visited that news site. Then when you visit a different website that also uses Google's ads, Google reads that same cookie and knows you visited both sites.
Over time, third-party cookies build a profile of your browsing habits — what sites you visit, how long you stay, what you search for, what you click on. Advertisers buy access to these profiles to show you targeted ads. A cookie alone does not contain your name or address, but it can be linked to other data to identify you.
This is why you see ads for something you looked at on one site appearing on another site hours or days later. The cookie followed you.
How to see, delete, and block cookies
Every major browser lets you manage cookies. In Chrome, go to Settings, then Privacy and Security, then Cookies and other site data. You will see a list of every site that has stored cookies on your device. You can delete all of them at once, or delete cookies from specific sites. You can also set the browser to delete cookies automatically when you close it.
Firefox, Safari, and Edge have similar controls. The exact path varies, but the principle is the same: look for Privacy, History, or Cookies in your settings.
Most browsers also let you block third-party cookies without blocking first-party ones. In Chrome, this is under "Block third-party cookies" in the Privacy and Security section. Blocking third-party cookies usually does not break websites, because the site itself (first-party) can still function. What stops working is the cross-site tracking.
You can also block cookies from specific sites while allowing them on others. This gives you fine-grained control: you might allow cookies on your bank's website but block them on news sites.
Cookie consent banners and why they exist
The banner that appears on many websites asking you to accept cookies exists because of laws, not because websites want to be transparent. The European Union's ePrivacy Directive and the General Data Protection Regulation (GDPR) require websites to get your permission before storing cookies that are not strictly necessary. California's Consumer Privacy Act (CCPA) has similar rules. Other countries and states have added their own requirements.
In practice, most consent banners are designed to make it straightforward to accept all cookies and hard to reject them. The "Accept All" button is usually large and prominent, while "Reject All" is small or hidden behind a "Manage Preferences" link. This is legal in most places, but it is not accidental — the design nudges you toward accepting.
If you click "Reject All" or "Manage Preferences" and uncheck third-party cookies, the website should respect that choice. Some sites will still try to set cookies anyway, which violates the law but happens.
The trade-off between convenience and tracking
Cookies make the web more convenient. They remember your login, your preferences, your shopping cart. But that same mechanism also enables tracking. A website cannot have it both ways — it cannot use cookies to remember you without also being able to track you.
The choice is yours. If you block all cookies, some sites will break or become annoying to use. If you allow them, you are trading privacy for convenience. Most people find a middle ground: allow first-party cookies so sites work properly, but block third-party cookies to limit cross-site tracking.
Browsers are slowly moving toward blocking third-party cookies by default. Chrome has announced plans to phase them out, though the timeline keeps shifting. Safari and Firefox already block them by default. This is not because cookies are dangerous — it is because regulators and privacy advocates have pushed back against the scale of tracking they enable.
What cookies cannot do
Cookies are often blamed for things they do not actually do. A cookie cannot see your files, access your camera, or install software. It cannot read cookies from other websites or see what you type into your password manager. It is just a text file that the website that created it can read.
A cookie also cannot follow you outside your browser. If you use a different browser, a different device, or an incognito window, the cookies do not travel with you. Each browser and each device has its own cookie storage.
The tracking that happens across sites is real and worth understanding, but it happens through cookies working as intended, not through cookies doing something sinister.
Frequently Asked Questions
Can I delete cookies without breaking websites?
Yes. Deleting cookies will log you out of sites and clear your preferences, but it will not damage anything. The next time you visit a site, it will set new cookies. You might have to log in again, but that is all. Deleting cookies is safe and reversible.
What is the difference between cookies and tracking pixels?
A tracking pixel is a tiny invisible image that a website embeds on a page. When you load the page, your browser downloads the pixel, and the server that hosts it learns your IP address and the page you are on. Pixels do not require storage on your device the way cookies do, but they serve the same purpose: tracking. Many sites use both.
If I block third-party cookies, will websites still work?
Almost always yes. Third-party cookies are mostly for advertising and analytics. The core functions of a website — logging in, reading content, making purchases — rely on first-party cookies. Blocking third-party cookies may mean you see fewer targeted ads, but the site itself will function normally.
Do I need to clear my cookies regularly?
No. Clearing cookies does not speed up your browser or improve security in any meaningful way. The only reason to clear them is if you want to remove your browsing history or log out of all sites at once. If you are concerned about tracking, blocking third-party cookies is more effective than regularly deleting them.
Can websites see my cookies from other websites?
No. A website can only read cookies that it set itself. A cookie set by Amazon cannot be read by Google. This is a fundamental security rule built into browsers. The only exception is third-party cookies, which are specifically designed to be read by multiple sites — but even then, only by the company that set the cookie.