Need help analyzing a CAP rate for a commercial property

[Cory St. Esprit]

I own 25 Subway franchises. One of the 5 unit strip malls that we rent in is for sale. I met with the landlord today to discuss. It's a NNN lease and I know the rents for all the units. 1 vacant as of recent but I expect it filled soon. I also know the property taxes, insurance, and CAM amounts since it's NNN. 3 long term tenants (including my Subway), 1 shorter term (2 years), and 1 empty unit but it'll prob be leased soon: Pizza shop with all FF&E.

Can someone point me towards a good tool to analyze the CAP rate and a good starting offer?