This is a very conservative spreadsheet for calculating towing capabilities. It's hosted on the Popup Explorer website. Click the link, then look on the lower right hand side for the spreadsheet download link.
This type of weight spread sheet can be useful, but it's important that the user understand the terminology being used. Where it asks for the Tow Vehicle "Dry Wt.", it's important for one to understand that "Curb Weight" is what vehicle manufactures provide (includes 150lb driver and a full tank of fuel), but the spread sheet doesn't allow for the weight of vehicle options. The "Note:" on the spread after "Dry Wt." is very important.
Also using the "Ship Weight" of a trailer rather than the "Dry Weight" will also increase the spread sheet accuracy as well.
I ran the spread sheet with my known TV/TT manufacture specified & CAT scale weights, and the results were respectfully close using the spread sheet.
2016 GM 2500HD 6.0L/4.10
2005 Jayco Eagle 278FBS
Reese HP Dual Cam
Putnam Class V