The labour cost of painting the outside of a house is hours multiplied by what an hour of your labour genuinely costs you, and both halves are more slippery than they look. The hours depend on wall area, coats, your crew's production rate and a preparation allowance that can exceed the painting itself. The cost per hour is not the wage on the payslip. Getting either wrong by a quarter puts the whole job out by a quarter.
Hours come from area, coats and a rate you measured
Wall area is the building's perimeter times its wall height, plus gables as half of base times height. Multiply area by coats and divide by your production rate in square feet an hour a coat, and you have painting hours. That is the easy part of the calculation and the part every rate published on the internet is trying to shortcut for you, with a number measured on somebody else's crew and somebody else's house.
Preparation hours are estimated separately, and they dominate
Washing, scraping, sanding, spot priming and caulking do not scale with area and are not inside a production rate. On a sound exterior they might be a day; on chalked and peeling siding they can be more than the painting. This is the input that separates a bid that makes money from one that does not, and it is the one that cannot be estimated from a photograph, which is why exterior work is walked before it is priced.
Your labour cost an hour is the fully loaded figure
Wage plus payroll taxes, insurance, holiday, training and the paid hours that are not spent on a wall. For most small painting businesses the fully loaded figure is meaningfully above the wage, and estimating against the wage is the commonest way a crew works a full week and finds nothing left at the end of it. Work out your own figure once a year and use it in every estimate.
Put the two together, then check it against a job you finished
On the worked example in the painting cost calculator, an exterior of 1,800 square feet at two coats, a production rate of 180 square feet an hour a coat and eight prep hours comes to 28.0 labour hours, which at a fully loaded $38 an hour is $1,064 of labour. Run a house you actually painted through the same arithmetic. If the answer is nowhere near what it took, the production rate or the prep allowance is the input to correct.
Questions people ask about labor cost to paint exterior of house
Is there a standard labour cost per square foot?
No, and any figure presented as one is an average across crews, regions and substrates that has very little to do with your next job. Labour cost per square foot is an output worth looking at after the fact, not an input worth pricing from.
How much of an exterior job is labour?
On most repaints, the large majority, which is why the production rate and the prep allowance matter far more than the price of the paint. Buying a cheaper gallon rarely rescues a job that was underestimated on hours.
Should ladders and scaffolding be in the labour figure?
Access changes how fast you cover surface, so the cleanest way is to estimate awkward elevations at a lower production rate rather than adding a vague uplift at the end. Equipment hire itself belongs as its own cost line.
What about two-storey houses?
They have more wall than their floor area suggests and a slower production rate on the upper elevations. Measure the wall rather than the footprint, and price the high work at the rate you actually achieve up a ladder.