In my experience it isn't about formulas but a good starting point is to ensure you know your PSI (personal survival income) and ASI (aspirational survival income) figures. I have a document that I use that enables you to include these plus costs, volumes and various margins that then give you a clear idea of your levels of investment and cash flow.
If this is helpful just send contact me at firstname.lastname@example.org
and I can send you the spreadsheet.
Steve Parker ICD International Company Development www.steveparkericd.com
SGood luck iflh me;y'p viaIiItsome of