I’ve been meaning to post this for a while. This is easily one of the best posts I’ve seen in recent years on budgeting your production. He includes several sample spreadsheets as well. You’ll certainly have most of what you need to put together your film budget. I used something very similar, albeit highly modified, for the latest doc.
The only thing I might add to get a really complete picture of what it will cost to get your film to market (vs. simply production as discussed here) is to budget out and add your market in plan: advertising, P&A, mastering and duplication etc. This will all vary depending on how you plan to get your film out there but at least you know you won’t come up short and be sitting on a film with no money left to gt it in front of people. I talked about about the nontraditional distribution approach we took with Half Devil Half Child in this post.
Here’s what Oliver Peters has to say: Film Budgeting Basics.