A factor I've always had in mind, which applied when I ran my own business, was to work on the basis that in a nominal forty hour week, which sort of begs the question, 'is there such a thing as a forty hour work week for a busy small or one person self employed business owner(?)', you will only invoice for approximately twenty eight hours of work. In other words your 'required' hourly, daily or weekly rate has to be made up from your billable hours which account for only approximately 70 per cent of your working time. So, for example, if you are to invoice for £1,000 of your labour or the work element (time) per week, because you're only able to charge for billable hours, i.e., ~28, your hourly rate equals ~£36 per hour. Non-billable hours are made up things such as machinery and workshop maintenance, sourcing materials, client and other business meetings (e.g., bank, accountant, etc), office work of various sorts, holidays, sickness, and so on. And, of course, other costs such as those you listed, e.g., overheads, equipment purchases, etc.- how much cash in the bank do I need each month
- then add on the taxes you will pay to take that home
- then add on the capital costs (equipment to purchase / replace / etc.)
- then add on the monthly overheads (workshop / website / accountant / petrol / etc.)
- calculate how many hours you want to work each day (remembering that the maximum work days in most jobs is 52 weeks x 5 days minus at least 28 days statutory holiday = 232 days) so if you need to earn £2,000 cash per month, that might need income of let's say £4,000 per month = £48,000 p/a = £206 per day or c. £25 p/h for an 8 hour day...
None the previous takes into account such items as materials used to make a products(s), business premise rent or rates, and so on, but I can see you've included some of those elements in your list above at the opening of the quotation. I'm just wondering how my example above fits into your more detailed outline posted earlier? Or maybe it's not relevant in the scheme you outlined? Slainte.