What is the maximum size of a cookie, and how many can be stored in a browser for each web site?

Question

I am learning about cookies, and I wonder about browser support when writing web applications that rely on cookies to store state.

• For each domain/web site,

Answer 1

Cookie Size Limits

If you want to support most browsers, then do not exceed 50 cookies per domain, and 4093 bytes per domain. That is, the size of all cookies should not exceed 4093 bytes.

Performance Thoughts

Cookies are sent on every request for a domain, this includes images. For arguments sake, lets say you have 30 resource on your website, and have 4093 bytes of cookies. That means the user is uploading 122Kb of data. So if I have a 1Mbit upload connection, that will take at least 1 second.

If you want to see the cookie test page I created, or read more about it check out Browser Cookie Limits.