Cookies are small files that websites store on your computer to remember information about you
A cookie is a text file that a website saves to your device when you visit it. The file is tiny — usually just a few kilobytes — and contains data the website wants to remember: your login information, items in your shopping cart, your language preference, or the fact that you've visited before. When you return to that website, your browser reads the cookie and sends it back, so the site knows who you are without asking you to log in again.
Cookies exist because the internet was originally built without memory. Each time you loaded a new page, the website had no way to know you were the same person who had just been there. Cookies solved that problem by letting websites recognize returning visitors and remember their choices.
Your browser stores cookies in a folder on your hard drive. You can see them, delete them, and control which sites are allowed to create them. Different browsers — Chrome, Firefox, Safari, Edge — store and manage cookies slightly differently, but the basic idea is the same across all of them.
Key Takeaways
- Cookies are small text files that websites store on your device to remember information about your visits and preferences.
- First-party cookies come from the website you are visiting, while third-party cookies come from advertisers or other companies tracking you across multiple sites.
- You can delete cookies, block them entirely, or allow only certain types through your browser settings without breaking most websites.
- Cookies do not install software, steal passwords, or give websites access to files outside the browser — they are just text files with limited data.
First-party cookies versus third-party cookies
A first-party cookie comes from the website you are actually visiting. If you log into your email, the email site creates a cookie so you stay logged in when you move between pages. If you add items to a shopping cart, that site creates a cookie to remember what you picked. These cookies are generally useful — they make websites work the way you expect them to.
A third-party cookie comes from a different company than the one running the website you are on. An advertising network might place a cookie on your device so it can track which sites you visit across the internet. A social media company might do the same. These cookies follow you from site to site and build a profile of your browsing habits. That profile is then used to show you targeted ads or sold to other companies.
Most browsers now block third-party cookies by default. Chrome, Firefox, Safari, and Edge all restrict them in their standard settings. This happened because privacy advocates and regulators pushed back against the practice of tracking people across the entire internet without their knowledge.
How cookies affect your browsing experience
Cookies make websites faster and more convenient. Without them, you would have to log in every single time you visited a site. You would lose your shopping cart if you closed the browser. Websites would not remember that you prefer dark mode or that you live in a specific country. The experience would feel broken.
On the other hand, third-party tracking cookies can feel invasive. You might notice that after looking at shoes on one website, shoe ads follow you to news sites, social media, and email. That is third-party cookies at work. Some people find this useful — they see ads for things they actually want. Others find it creepy and prefer to block them.
You can control your cookie experience through your browser settings. You can delete all cookies, block third-party cookies, block all cookies from specific sites, or allow cookies only while you are actively using a site. The tradeoff is that blocking too many cookies can break some websites — they may not remember you, or certain features may not work.
Session cookies versus persistent cookies
A session cookie exists only while you are using a website. It disappears when you close your browser. These are usually first-party cookies that help a site function while you are there — keeping you logged in, remembering your shopping cart, tracking what page you are on.
A persistent cookie stays on your device even after you close the browser. It has an expiration date set by the website, which might be days, months, or years away. Persistent cookies are often used to remember your preferences or to track you across visits. Many third-party tracking cookies are persistent, which is why they can follow you across the internet for weeks or months.
What cookies cannot do
Cookies have real limits, and understanding them helps separate fact from fear. A cookie cannot install software on your computer, run programs, or access files outside the browser. It is just a text file with data in it. A cookie cannot steal your passwords — it can only store information the website itself gave it. A cookie cannot see your screen, access your camera or microphone, or read your email.
A cookie also cannot follow you outside your browser. If you use your phone's native app for a service, that app does not read your browser cookies. Cookies are browser-specific, so cookies stored in Chrome do not appear in Firefox, and neither browser can see cookies from your phone.
Cookies also cannot identify you by name or social security number unless you gave that information to the website first. A cookie might contain a number that the website uses to look up your account, but the cookie itself is just a code. Without access to the website's database, the cookie is meaningless.
How to manage cookies in your browser
Every major browser lets you control cookies through settings. In Chrome, go to Settings, then Privacy and Security, then Cookies and Other Site Data. You can choose to block all cookies, block third-party cookies only, or allow all cookies. You can also see which sites have stored cookies on your device and delete them individually.
Firefox has similar controls under Settings, Privacy and Security, Cookies and Site Data. Safari on Mac and iPhone blocks third-party cookies by default and lets you delete all cookies through Settings. Edge, Microsoft's browser, has cookie controls under Settings, Privacy, Cookies and Other Site Data.
You can also delete cookies manually. In most browsers, pressing Ctrl+Shift+Delete (Windows) or Command+Shift+Delete (Mac) opens the Clear Browsing Data window. You can choose to delete cookies from a specific time period or all of them at once. Deleting cookies will log you out of websites and reset your preferences, so you may need to log back in.
Cookies and privacy laws
Different countries have different rules about cookies. The European Union's General Data Protection Regulation (GDPR) requires websites to ask permission before storing non-essential cookies. Many European websites show a banner asking you to accept or reject cookies when you first visit.
California's Consumer Privacy Act (CCPA) gives residents the right to know what data websites collect and to ask for it to be deleted. Other U.S. states have passed similar laws. These laws do not ban cookies, but they require websites to be transparent about what they are doing and to give people control over their data.
Because of these laws, most websites now have a privacy policy that explains what cookies they use and why. Reading that policy is one way to understand what data a site is collecting about you.
Frequently Asked Questions
Should I delete my cookies regularly?
It depends on your preference. Deleting cookies improves privacy because tracking cookies are removed, but it also logs you out of websites and resets your preferences. If you block third-party cookies in your browser settings, you get most of the privacy benefit without the inconvenience of deleting cookies manually.
Can cookies give me a virus or malware?
No. A cookie is a text file — it cannot execute code or install software. Malware comes from other sources: malicious downloads, compromised websites, phishing emails, or unpatched software. Cookies are not a vector for infection.
What is the difference between cookies and tracking pixels?
A tracking pixel is a tiny invisible image that websites embed in pages or emails. When you load the page or open the email, the pixel loads from a server, and that server records that you viewed it. Pixels are another way to track you, but they work differently than cookies. Pixels do not store data on your device — they just report back to a server.
Do I need to accept cookies to use a website?
Most websites require first-party cookies to function — you cannot stay logged in or use a shopping cart without them. However, you should not have to accept third-party tracking cookies. If a site refuses to work unless you accept all cookies, you can try blocking third-party cookies in your browser settings and reloading the page.