Here is a really quick way to do it:
Put all your clips into one bin or folder, use the find function if you don’t want to actually move them.
Select all the clips and then right click (or control click) and scroll down to Media Manager.
In Media Manager, under the “Media” option use the drop down menu to select “Copy”.
Hover your mouse over the “Modified” green bar till it highlights, under the green bar the total media length and file size will magically appear.
Ta Daa.
When you are done just cancel.