If you are using Outlook 2003, you can find the size of your PST file by following these steps:
- In Outlook go to menu File --> Data Management
- Then select the "Personal Folders" file that starts with the Outlook.pst file name by clicking on the entry.
- Next, click on the "open folder" icon above the link.
- You will see the contents of the folder, including your PST file. Right click on the file and select Properties and you will see the size of your Outlook file.