To check the size of a folder on Baidu Pan (pan.baidu.com) without downloading it, you can do the following:

• Log in to your Baidu Pan account via a web browser.
• Navigate to the folder you are interested in.
• The folder size is usually displayed next to the folder name in the list view, often in a format like "1.2 GB" or "500 MB". If you hover over the folder, you may also see a tooltip with the total size.

If the size is not immediately visible, try selecting the folder (by checking the box next to it). The total size of the selected folder should appear at the top or bottom of the file list.

If you do not have an account or are accessing a shared folder, some third-party tools or browser extensions may help, but the most reliable way is to use the official Baidu Pan web interface as described abovemultcloud.com+1.