How Much Paint for Exterior Siding?
Exterior paint is estimated from the wall area, not the floor area. Here is how to get there.
A typical 1,500 square foot house needs roughly 12 to 14 gallons of paint for two coats on the siding. That comes from about 2,000 square feet of paintable exterior wall. Exterior surfaces are rougher than interior walls, so they absorb more — this is the single biggest reason exterior estimates come up short.
Estimates only. Textured walls, high ceilings, sprayers and major colour changes can all increase the amount you need. Always buy slightly more than the calculation suggests.
Exterior paint by house size
| Room / surface | Surface | Coats | Paint | Paint cost |
|---|---|---|---|---|
| Small house, 1,000 sq ft, one storey | 1,300 sq ft | 2 | 9 gal | $405 |
| Average house, 1,500 sq ft, one storey | 2,000 sq ft | 2 | 14 gal | $630 |
| Average house, 1,500 sq ft, two storeys | 2,600 sq ft | 2 | 18 gal | $810 |
| Large house, 2,500 sq ft, two storeys | 3,200 sq ft | 2 | 22 gal | $990 |
| Average house, smooth siding | 2,000 sq ft | 2 | 12 gal | $540 |
| Average house, one coat | 2,000 sq ft | 1 | 7 gal | $315 |
Estimates based on one storey of paintable wall. Two storeys of the same footprint roughly doubles the wall area. Two coats at 300 sq ft per gallon — the realistic figure for textured siding.
Why I give you an estimate instead of a formula
Interior calculations are precise because rooms are rectangles. Exteriors are not: gables, dormers, bay windows, differing storey heights and attached garages all break the simple maths.
If you want an accurate figure, measure it. Walk the house and add up the horizontal length of each wall, multiply by the height of that wall, then subtract your windows and doors. That is the only number you should buy paint from.
The table above is a starting point for budgeting, and it uses this rough relationship: a single-storey house has roughly 1.3 square feet of paintable wall per square foot of floor area. A 1,500 square foot house therefore has around 2,000 square feet of siding. Treat it as a budget figure, not a purchase order.
The multipliers that make exterior jobs run out
Four things consistently push exterior paint use above the calculation:
- Texture. Smooth hardboard covers 350 to 400 square feet per gallon. Rough-sawn wood, stucco and textured fibre cement cover 200 to 250. This alone can double the paint.
- Bare or weathered wood. The first coat on thirsty siding can disappear at 150 square feet per gallon.
- Colour change. Going from dark to light on exterior siding usually needs three coats, not two.
- Spraying. If you spray rather than brush and roll, add 20 to 30 % for overspray.
On an exterior job, buy the extra. A half-finished house with an obvious colour break between batches is far worse than a spare 5-gallon bucket.
Buy in one batch, always
Exterior paint is the one place where batch matching is critical. You are painting large, flat, adjoining surfaces in full daylight — exactly the conditions where a slight tint difference between two batches is most visible.
Buy all the paint for one wall, or for the whole house, in a single purchase and mix the containers together in a large bucket before you start. That is standard practice among professional painters and it takes ten minutes.
Frequently asked questions
How much paint to paint a house exterior?
A 1,500 square foot single-storey house needs roughly 12 to 14 gallons for two coats. Two-storey houses of the same footprint roughly double the wall area.
How many square feet does a gallon of exterior paint cover?
300 to 400 square feet on smooth siding, but only 200 to 250 on rough-sawn wood, stucco or textured surfaces. Always check the label and assume the lower figure on texture.
Do I need two coats on exterior siding?
Yes, normally. One coat is only enough when refreshing the same colour on sound siding. A colour change usually needs three.
How long does exterior paint last?
Five to ten years for a quality exterior acrylic on properly prepared siding. Preparation matters more than brand — paint over a poorly prepared surface fails early regardless of what you paid for it.