Since Windows Live Hotmail started offering virtually unlimited storage space for your emails, and lets you store documents and pictures on SkyDrive, the size of your email folders is no longer much of a concern. However, if you need to know how large an email folder is, either inbox or any other folder, Hotmail gives you that answer in a special screen. This tutorial explains how to access that screen, and view not only the size of each email folder, but your grand total size used on disk for all emails in your Hotmail account, with a breakdown of number of messages per folder.
To access the global breakdown of email folder sizes and number of messages per folder, start by logging into your Hotmail account. If you are not inside your inbox (depending on your settings, you may be on the Windows Live Home screen), click on the "Go to inbox" link, as shown on the screenshot below:
Once you are inside your inbox or other email folder, move your cursor (mouse pointer) above the "Folders" link / button on the left hand side, and Hotmail will show a gear icon in overlay - click on it: from the menu, select "Manage folders".
Hotmail.com will now redirect you to a page that contains a listing of all the email folders in your account, including the six standard folders (Inbox, Junk, Drafts, Sent, and Deleted), as well as any custom folder you have created yourself:
As you can tell from the screenshot above, Hotmail includes the folder name on the left ("Folder" column). For each email folder, the "Messages" column gives you the total number of emails the folder in question contains (both Read and Unread emails), and the "Size" folder gives you the total amount of storage space occupied by that particular folder and all the messages it includes.
If you scroll to the very bottom of that screen, Hotmail will give you a "Total" line (row) that summarizes the total number of emails in your account, and the total amount of space they are using: (first total is message count, second is total space)
This is all it takes to figure out how many emails are in your Hotmail account, and the amount of space you are currently using; this screen is always up-to-date when you load it, but does not include any email messages you may receive afterwards (until you manually reload that screen or visit it later on of course).