Originally published here: https://nickgrattan.wordpress.com/2008/04/29/finding-the-id-guid-for-a-sharepoint-list/
There are times when you need to find the Id (a Guid) of a list – for example, when using jquery to pull data from a list. Here’s a simple way of doing this:
Navigate to the SharePoint list using the browser.
Select the Settings + List Settings menu command.
Copy the Url from the browser address bar into Notepad. It will look something like:
…../CountryTemplate/_layouts/listedit.aspx?List=%7B874DE9AE-FFE3-4851-8801-8D35C7BD3187%7D
Delete everything before and including “List=”
To be left with
%7B874DE9AE-FFE3-4851-8801-8D35C7BD3187%7D
Now put this into a text editor such as notepad use find replace to
Change “%7B” to “{”
Change all “%2D” to “-“
Chnage “%7D” to “}”
You are now left with the Id:
{874DE9AE_FFE3_4851_8801_8D35C7BD3187}
Which is the GUID