Exterior Painting Calculators

Exterior work is priced by surface, not by room, because each material behaves differently. Vinyl siding, stucco, brick and bare timber take wildly different amounts of paint for the same measured area, and the preparation each one needs varies even more than the coverage does. These calculators handle each surface on its own terms.

Pick the surface you are painting below. If you want a single figure for the whole outside of a property rather than one surface at a time, use the whole house calculators.

Pick your surface

Coverage outside is not coverage inside

This is the thing that catches people out. A smooth interior wall might take paint at close to the rate on the tin. A rough exterior surface will not come near it.

Stucco and textured render have far more actual surface area than their measured area suggests, because the texture is three dimensional. Brick is porous and absorbs the first coat rather than sitting on top of it. Rough sawn timber and weathered cladding both drink product. Chalky, oxidised aluminium needs sealing before anything will bond properly. In each of those cases the real spread rate can be a long way below the label figure, and ordering to the label is how a job runs out of paint on the last elevation.

Each calculator above already uses a working figure for its own material rather than one generic number. The underlying explanation is in how much does a gallon of paint cover, and whether you need to seal first is covered in do I need primer before painting.

Measuring an exterior

Measure by elevation. Walk each face of the building, take the width and the height to the eaves, and record them separately rather than trying to work out a single total. Gables are triangles, so take the width and the height to the ridge and halve the product. Anything separate, such as a garage or an outbuilding, is measured on its own.

Trim, fascia, gutters and downpipes are measured in linear feet, not area. That is why they have their own calculators: pricing a linear item as though it were an area is one of the fastest ways to get an exterior quote wrong. The full walk round method is in how to measure a house for exterior paint.

Access is a cost, and it is not in the area

A wall you can reach from the ground and the same wall at second storey height take the same amount of paint and very different amounts of time. Ladders, towers, scaffold, sloping ground, conservatories you cannot ladder over and neighbours whose permission you need all add hours that no area based figure will show you. Price access as its own line rather than hoping the square footage absorbs it.

Preparation dominates exterior labour

On a sound, previously painted surface, prep is a wash down and a few repairs. On a weathered one it is scraping, sanding, filling, treating bare timber and spot priming, and it can take longer than the painting itself. Exterior jobs where the prep was priced as an afterthought are the ones that lose money, which is why how to account for prep time in a painting estimate is worth reading before you commit to a figure.

Weather is part of the estimate

Exterior coatings have temperature and humidity limits, and a job that has to stop for rain or start late because of dew is a job that costs more in crew days than the surface area implies. Building a weather allowance into the schedule is normal practice rather than pessimism, and it is one of the reasons exterior work is often better priced by the crew day. See painting crew day rate.

If you are quoting this for a customer

The calculators give you job cost. Turning that into a price means adding your overhead recovery and your profit on top, using a labour figure that reflects what an hour truly costs you. The method is in painting labor burden and painting business overhead, and the tools that assemble the whole stack are in the contractor pricing calculators. If exteriors regularly come in tight, how to avoid underbidding a painting job is the place to start.

Coverage and production, surface by surface

These are the working figures the calculators on this page run on. They are not the numbers printed on a tin, which assume a smooth sealed surface in ideal conditions. Coverage below is what these materials actually achieve outdoors.

The spread of that first column is the whole argument for pricing exteriors by surface rather than by house. Brick at 150 square feet per gallon and siding at 350 differ by more than a factor of two. Measure the same area on each and you buy very different amounts of paint.

Why the spray column is not a shortcut

Spray rates look transformative, and on open siding they are: 500 square feet an hour against 175 by brush. But spraying an exterior needs masking of windows, doors, roofs, planting and anything downwind, and that masking time does not appear in a production rate. On a house with a lot of trim and glass, the preparation can take back most of the gain.

Trim is the clearest case. At 80 square feet an hour by brush it is the slowest surface here per square foot, and it is usually cut in by hand regardless of whether the body was sprayed.

What each surface will catch you out on

Frequently asked questions

Why does exterior paint cover less than the tin says?

Because the label figure assumes a smooth, sealed, primed surface. Stucco and render have far more real surface than their measured area, brick and bare timber absorb the first coat, and weathered or chalky surfaces need sealing before anything sits on top. Each calculator above uses a working rate for its own material instead of one generic figure.

How do I measure a house for exterior painting?

Elevation by elevation. Take the width and the height to the eaves for each face, treat gables as triangles by halving width times height to the ridge, and measure outbuildings separately. Trim, fascia, gutters and downpipes are measured in linear feet rather than area, which is why they have their own calculators.

Do I need to include the trim and gutters separately?

Yes, if you want the number to be right. Linear items priced as though they were areas go wrong quickly, and trim often carries a different product and a much slower production rate than the wall behind it. Use the trim and gutter calculators alongside the siding or stucco figure.

Does access affect the cost?

Considerably, and it does not appear in the measured area at all. Height, ladders, towers, scaffold, sloping ground and obstructions all add hours to the same square footage. On multi storey or awkward properties access can be a larger variable than the surface itself.

Can I paint brick, and should I?

You can, with a breathable masonry product, but it is close to permanent: getting paint back off brick is difficult and expensive. Brick also has a low spread rate because it is porous, so budget more product than a smooth wall of the same size. The brick calculator uses masonry figures rather than general exterior ones.

Are these calculators free?

Yes, all of them, with no signup and no email address. They run entirely in your browser. The paid product is a separate quoting tool for contractors who need to send branded estimates.

Why does brick need so much more paint than siding?

Brick is porous and textured, so it takes paint at about 150 square feet per gallon against roughly 350 for siding. The same measured wall area needs more than twice the product. Stucco sits between them at about 200 for the same reason.

Is spraying always faster on an exterior?

On open siding, considerably: around 500 square feet an hour against 175 by brush. But the masking that spraying requires is not in that figure, and on a house with a lot of glass, trim and planting it can take back most of the saving.