When you browse the web, websites quietly leave things behind in your browser. Two of the most common are cookies and local storage. They sound similar and often get confused, but they work differently and have different privacy implications. This guide explains the difference in plain language.
What a cookie is
A cookie is a small text file a website stores in your browser to remember information about your session. It is sent back to the site on every request, which is how the site knows you are logged in or what is in your cart. Cookies have a size limit (about 4KB each) and they expire.
For the full background on cookies, see our browser cookies explained article.
What local storage is
Local storage is a larger, more modern storage area in the browser. Like cookies, it is tied to a specific site — one site cannot read another's local storage. But unlike cookies:
- It has a much larger capacity (typically 5MB or more per site).
- It is not sent to the server with every request; it stays on your device and is read by the site's scripts when they need it.
- It does not expire automatically; it stays until the site or you remove it.
The key differences
| Cookies | Local storage | |
|---|---|---|
| Size limit | ~4KB per cookie | ~5MB+ per site |
| Sent to server with every request | Yes | No |
| Expires | Yes (session or set date) | No (persists until cleared) |
| Server can read/write | Yes | Only through site scripts |
| Privacy risk | Can be used for tracking | Harder for outside companies to reach |
What each is used for
Cookies are used for things the server needs to know on every request: login sessions, session IDs, and shopping cart state.
Local storage is used for things the browser can remember without bothering the server: UI preferences, cached data, offline content, and settings that personalize the page.
Plenty of sites use both at once. A cookie might hold a session ID that proves you are signed in, while local storage holds the settings that personalize the page.
The privacy difference
Tracking usually leans on cookies — especially third-party cookies — which is why browsers have started blocking those by default. Local storage is harder for outside companies to reach, since it belongs to the site you are actually on and is not sent to other domains.
That does not mean local storage is private by default. The site itself can read it, and a malicious site can use it to store tracking identifiers of its own. But it is not the cross-site tracking vector that cookies are.
How to clear them
Both are cleared together under your browser's "clear browsing data" or "cookies and site data" settings. See the browser cookies explained article for exact paths in each browser.
Quick answers
Are local storage and cookies the same? No. Cookies are small text files sent to the server with each request and they expire. Local storage is larger, stays on your device, and does not expire.
Is local storage a privacy risk? Less than cookies. It is tied to the site you visit and is not sent to other domains, so it is harder for third parties to use for cross-site tracking. The site itself can still read it.
How do I clear both? Use your browser's "clear browsing data" or "cookies and site data" setting. It removes cookies and local storage together.
Why do websites use both? Cookies handle things the server needs to know (logins, sessions). Local storage handles things the browser can remember without the server (preferences, cached content).
Sources and further reading
Written by Hassan Arshad, founder of UsefulOrbit. Last updated August 31, 2026.