An exterior painting estimate is the same arithmetic as an interior one and a completely different job. The area is easier to measure and the coats are easier to decide, but the two inputs that actually settle the price, preparation and access, are the two that no square foot rate can carry. A house and a barn of identical surface area can differ by a factor of three in hours, and everything difficult about exterior estimating is contained in that sentence.
Area on an exterior is a wall calculation, not a footprint
Take the perimeter of the building and multiply by the wall height, then add gables as triangles: base times height, halved. Do not price from the floor area of the house, because a fifteen hundred square foot single storey and a fifteen hundred square foot two storey have very different amounts of wall on them. Soffits, fascias, trim and doors are usually estimated separately in linear feet or by count, because they run at a different production rate to open siding.
Preparation is the estimate, not a line on it
Washing, scraping, sanding, priming bare wood, caulking joints and replacing failed sealant are hours that have nothing to do with how much paint the job will take. On a sound five-year-old exterior they might be a day; on chalked, peeling siding they can exceed the painting itself. This is why an exterior estimate that has not been walked is a guess, and why the honest thing to do with an unseen house is to price the walk rather than the job.
Access changes your production rate, so change the rate
A crew rolling siding at ground level and the same crew working from ladders above a conservatory roof do not cover surface at the same speed. Rather than adding a vague contingency at the end, estimate the awkward elevations at a lower production rate than the easy ones. The total comes out in the same place and the estimate becomes something you can explain, defend and learn from when the job is finished.
Lead work on older houses is a separate question entirely
Anyone paid to perform work that disturbs paint in housing built before 1978 must be certified in lead-safe work practices under the federal renovation programme, and that includes sole proprietorships. Approximately three-quarters of United States homes built before 1978 still contain some lead-based paint. Whether that applies to a given exterior is a question for the rules and your own certification, not for an estimate template, but it is a cost that belongs in the number rather than discovered on site.
Questions people ask about exterior painting estimate
How many coats does an exterior need?
Two over a sound, similar-coloured existing finish; more where you are covering bare substrate, a strong colour change or a chalked surface that has taken a primer. The estimate should say which, because a customer comparing two bids has no way of knowing that one of them assumed one coat.
Should I price washing separately?
It is worth its own line, because it is the item most often assumed by the customer and most often left out of a cheaper competing bid. Separating it makes the comparison honest and gives you something to remove if the customer wants the price down.
How do I estimate a house I have not seen?
You do not, beyond a range. Substrate condition is the largest single variable in exterior work and it is not visible from a street view. Giving a range with the reason attached, then pricing properly after a walk, loses fewer jobs than a firm number you later have to raise.
What about weather delays?
Price the work, not the calendar, and say in writing that the schedule depends on conditions. Building weather contingency into an hourly figure hides it; stating it as a scheduling term keeps the price defensible and the expectation set.