A painting estimate looks like a price and is really four decisions: how much surface there is, how many coats it is getting, how fast your crew covers surface, and how many hours of preparation the job needs before any paint goes on. Everything after that is arithmetic. The reason estimates go wrong is almost never the arithmetic; it is that one of those four was guessed, and the one most often guessed is the one that moves the answer furthest.
Measure the area first, and measure it properly
Wall area is the room's perimeter times the wall height. A twelve by twelve room with eight foot walls has a forty-eight foot perimeter, so three hundred and eighty-four square feet of wall, plus a hundred and forty-four of ceiling if the ceiling is in scope. Openings come off only when they are large enough to matter, because a standard door is a rounding error next to the cutting-in it adds around its frame. An area taken from a doorway rather than a tape is the single commonest reason an estimate is wrong before any rate is applied to it.
Use your own production rate, not a published one
A production rate is how much surface your crew covers in an hour, per coat. It varies with the surface, the method and the people, and a rate averaged across crews you have never met tells you very little about yours. Time one real room, in square feet an hour a coat, and use that number. It will change the estimate more than the paint price, the margin or anything else on the page, which is why borrowing it is the most expensive shortcut in estimating.
Price the preparation as its own line
Masking, filling, sanding, caulking and moving furniture do not scale with wall area and are not covered by a production rate at all. A newly plastered wall and a hundred-year-old stairwell can have identical square footage and differ by a day of preparation. Estimating prep in hours, separately, is what stops old houses quietly consuming the margin, and it gives you something to point at when a customer asks why two rooms of the same size were not the same price.
Turn cost into price with a margin, not a markup
Labour hours times your fully loaded labour cost, plus gallons times what a gallon costs you, is what the job costs you. The price that leaves the margin you want is that cost divided by one minus the margin, not the cost multiplied by one plus it. On a job costing $1,526.86 those two arithmetics differ by around $290 at a 35% margin, which is most of a day's labour, and a business that uses the wrong one believes it is earning more than it is on every job it prices.
Questions people ask about painting estimate
Should the estimate show a price per square foot?
Only if you want to be compared on it. A square foot rate hides prep, which is the part that varies most between jobs, so quoting one invites a customer to compare a stairwell against a bedroom. Working the estimate from area, coats, rate and prep and then presenting a job price keeps the conversation on the work rather than on a rate.
How long should an estimate stay valid?
Long enough to be honest and short enough to be safe, which for most contractors is thirty days. Paint prices and crew availability both move, and an estimate a customer accepts in March that was priced in November is a job you have agreed to do at last year's costs.
What should I put in writing?
Scope, surfaces, coats, the products, what preparation is included, what is excluded, and the price. Almost every dispute in painting is about what was included rather than about the number, and the estimate is the only document that answers it.
Does this site publish painting rates?
No. There is no book rate or price per square foot anywhere on this hub, deliberately. Every figure on these pages comes from the numbers you enter, because what a job sells for depends on your costs, your town and who else is bidding.