Why this painting calculator counts gallons, not floor space
Gallons follow the surfaces you actually paint. A house with tall ceilings, lots of trim or a dark color that needs another coat uses more paint, and every one of those gallons also takes time to cut in and roll. The floor area of the house knows none of that.
So the calculator asks how many gallons the job takes and turns each one into painter hours and materials. In the example, 31 gallons of wall, ceiling and trim paint carry 91.14 painter hours, 2.94 hours a gallon, and $42.30 a gallon of paint and sundries at cost.
Getting the gallon count right before you bid
Measure the wall area room by room, the ceilings, and the trim, then divide by the coverage printed on the can for each coat. The example uses 20 gallons of wall paint for two coats, 6 of ceiling white, 4 of trim enamel and 1 of primer for patched spots.
The hours per gallon change with the work. Trim with a brush takes much longer per gallon than rolling a ceiling, and every window that needs masking adds time without adding paint. If a house is trim-heavy or full of windows, push the hours per gallon above 2.94. Setting it to 3.2 on the example raises the price to $8,726.10.
A 20-gallon repaint with no scaffold or extra color
Not every house needs a scaffold for a foyer or a third color. Set the gallons to 20, the scaffold rental to zero and the extra color to zero, and the job comes to $5,339.04, about $266.95 a gallon.
The price per gallon barely moves, because the only fixed line left is the $299 for running the van, the sprayer and the ladders. That cost is real on every job, so on a single bedroom it weighs much more per gallon. A bedroom that takes 3 gallons still needs the van loaded, the drop cloths down and the brushes washed at the end of the day. The $400 minimum keeps a one-room job from going out at a loss.
Stages, tools and the $8,663 painting spreadsheet price
The $49 break-even rate is the example company's $49.25, rounded, covering wages, the van, insurance and the hours spent quoting. The painting hourly rate page shows how the example gets there, and the free true hourly rate calculator builds yours. The 50% markup on paint covers your store runs and waste.
The spreadsheet costs each tool by its running hour, keeps every paint and sundry on a price list, sets labour by stage, adds a cushion, lists the painting hours owners forget, prints a customer quote and logs each job's real hours. Its price for this house is $8,663. For room and day rates painters quote, see the painting pricing guide.