@l2e Hey there! I own a full service painting business in Maine.
8x8x8 is 64 sq ceiling, 256 walls, x number of window frames, doors, door frames
8x4- 48 ft of baseboard trim.
Labor standards examples - 100 sq ft wall painting per hour2-3 df per hour, 1 door per half hour, 3 wf/hour
Say its color change - 512/100 = 5.1 hours for paint application - in reality, drop cloths, wall/trim wipe down and cleaning, prep like minor caulking against trim, hole fills w/ mud or spackling would be included in that for me, as any of my guys or me can paint a coat onto a room of this size in an hour or less. You can try out different labor standards, and find what works best for you.
call it 1 hr minimum for a fresh 1 coat on ceiling. 30 min for floor prep, removal of outlet covers, door hardware maybe, etc.
400 sq for a gallon of GOOD paint (eg sherwin, benjamin moore, a handful of others) is safe, but I often do 350 to be safe. If 2 coats, just do 200 instead of 400. If it's 500 some odd square for 2 coats, that's 2 gallons, always round up. I charge about a 40-50% markup on paint gallons (trust me they get expensive) which gets eaten up in things like fresh brushes, rags, drop cloths, roller covers, and other 'soft supplies'. Some people also do things like charge $5 per $100 etc etc.
If there's failing drywall tape, holes, repairs, door removal, yada yada anything beyond basic hole fills/caulk etc, charge for that. There's an endless number of variables that might influence you to charge more or less for any one project.
I do 75% exterior and about 25% interior, although that is changing as of the last couple years as we are gaining more commercial clients and facing a lot of indoor projects of a different type than standard residential repaints. Exteriors are even easier to estimate, 99% of houses have '4 sides', you measure them for siding sq footage, count window frames, door frames, soffits, fascia board linear footages, and multiply by labor standards.
Essentially I'll be at at least "1 day" of work regardless of the project, because that's just kind of my minimum, which is generally $750, and for one room as you mention with two coats and one on ceiling/trim (color match, different color walls), I'd be 750-950 depending on various things, including their physical location (maine is a big state when you service all of it).
When it's peak exterior season in spring and it's high urgency for customers to book, I comfortably use these methods at $75 per hour estimated, sometimes more, and sell 40-50% estimates. With small tweaks, we have managed to get this above 50% in many months. Professional painting businesses, when their systems are dialed in, generally come across as much safer bets to homeowners, and I can charge premium prices because I have plenty of estimates to do, and there is a system that customers can trust to know their project will ACTUALLY be completed. Simply answering the phone, doing an appointment, and delivering an estimate is substantially more than they get from the majority of contractors they reach out to in my state.
I use slightly different standards for exteriors, and implement both a sales and project management process, but yeah that's basically the gist of it.
Edit: I take 20% down, 80%/remaining balance at project completion. Because we are in Maine and it's basically seasonal work (for the most part), I primarily subcontractors whom I source the same way I would employees, but who work for contract prices instead of per hour. You'll see many people trash this method, but trust me, unless you really find a some golden geese and incentivize them with substantial performance bonuses, it's nigh impossible to meet the demand for exterior work and then keep all those same guys busy through a cold, snowy winter. We have 5-10x the amount of people completing projects in summer than we have in winter, and frankly, they are much more motivated than employees who have no real motivation to work quickly considering they are paid by the hour.
You want to foster responsibility in your crews, have them understand that it's their job to ensure the work is done correctly (even if you're managing the project), and your best crews/painters will make WAY more money than they would as employees. Plus, maine is pretty damn lax about their independent contractor rules/standards. It's just some simple paperwork, and then you issue 1099's. As you grow, you will find a handful of employee painters to keep busy year round, maybe.
