I have done a small tool in excel for people who are looking to set up some type of consulting business.
You can plug in how much you charge per hour, how many clients you see and then put in expenses.
The tool allows you do some basic analysis on revenue and costs in the first few months and work out what you can afford to pay in rent and alike.
What the tool looks like is on scribd sorry I can’t work out out to get a download of just the excel file.
If you would like a copy you can email me firstname.lastname@example.org also happy to do any ammendments if you would like.