How Large Can a Single Cookie Be? - PHP Script Tips - Understanding and Managing Cookies

How large can a single cookie be? The answer is depending what is the Web browser your visitor is using. Each browser has its own limit:

• Internet Explorere (IE): about 3904 bytes
• Mozilla FireFox: about 3136 bytess

If you want to test this limit, copy this sample script, huge_cookies.php, to your Web server:

<?php
  if (isset($_COOKIE["HomeSite"])) {
    $value = $_COOKIE["HomeSite"];
  } else {
    $value = "";
  }
  $value .= "http://dev.FYICenter.com/faq/php";
  setcookie("HomeSite", $value);
  print("<pre>\n"); 
  print("Large cookie set with ".strlen($value)." characters.\n"); 
  print("</pre>\n"); 
?>

Open your browser to this page for first time, you will see:

Large cookie set with 32 characters.

Click the refresh button, you will see:

Large cookie set with 64 characters.

Keep clicking the refresh button, you will see the limit of your browser.