How to create Sum Formula across multiple workbooks

[SuzanneLouise]

Hi. I am trying to sum across multiple workbooks, creating an aggregate pipeline for my sales team. I have tried the lookup but it keeps giving me an error.

[FDibbins]

hi and welcome to the frum

you will have to provide much more info than that...are the formats/layouts on each sheet the same...where are the values you want to add.

i would suggest you upload a sample work book, (all sensitive data removed), showing what data you are working with, a few examples of what your expected outcome is, and how you arrived at that
To attach a file to your post,
click advanced (next to quick post),
scroll down until you see "manage file",
click that and select "add files" (top right corner).
click "select files" find your file, click "open" click "upload" click 'done" bottom right. click "submit reply"

Once the upload is completed the file name will appear below the input boxes in this window.
You can then close the window to return to the new post screen.