Budgeting to start a business

[eggofmantumbi]

For many years I've wanted to stay a business. I've got my idea and have even seen great premises available.
I'd really like to find some kind of spreadsheet template/ app which could help me figure out if my idea is really viable. Has anyone found something live this? Something that would help me figure out if I could make it work?

Thanks

Do you need a premises? Not all businesses need much start up funds- I think that is a myth often created by financial "advisors" keen to sell loans.