How do I check the size of folders in my mailbox?

There are a number of ways to do this. The most common is:

1. Open Outlook
2. Click File in top right corner
   
3. Click Tools
   NOTE: You may need to scroll down if Outlook is currently not full screen.
   
4. Click Mailbox Cleanup... in the Mailbox Cleanup pop up
   
   
5. Click View Mailbox Size...
6. Check which folders contain large amounts of data
   
   NOTE: Folder sizes will be displayed in kilobytes (KB). To covert to megabytes (MB), move the decimal point three places to the left. For example, 4742 KB is roughly 4.7 MB. For the exact figure, divide the KB value by 1024.
   
7. Click Close on the Folder Size pop-up
8. Click Close on the Mailbox Cleanup pop-up
9. Click the back arrow in the top right hand corner to return to your mailbox
   
10. Commence cleaning your mailbox according to the folders with the most size. Instructions on how to archive can be found on the create a PST/Archive folder page.