How much exterior paint do I need for a house? (1,000 to 3,000 sq ft)
A single-storey 30 x 40 ft house needs about 9 gallons of exterior paint for two coats on smooth, previously painted siding (8.2 gallons at 350 sq ft per gallon for its 1,429 sq ft of wall with two doors and twelve windows deducted), or 12 gallons on rough cedar, stucco or bare fibre cement at 250 sq ft per gallon. A two-storey 30 x 40 ft house needs 16 gallons smooth or 22 rough. Trim is extra: about 2 gallons for the ranch, 2 for the two-storey. The tables cover 24 x 40 to 40 x 60 ft, one and two storeys, and the metric houses.
How many gallons of exterior paint for one and two storey houses?
Gross wall area is perimeter x 10 ft per storey plus two gable ends at a 6/12 pitch; doors (20 sq ft) and windows (13 sq ft) are deducted. Gallons are exact for two coats; the cans column is what you buy. Coverage of 350 sq ft per gallon on smooth siding and 250 on rough follows typical exterior paint labels; check the number on yours.
| House | Floor (sq ft) | Wall to paint (sq ft) | Smooth (gal) | Buy | Rough (gal) | Buy |
|---|---|---|---|---|---|---|
| 24 x 40 ft, 1 storey | 960 | 1,254 | 7.2 | 8 | 10 | 11 |
| 30 x 40 ft, 1 storey | 1,200 | 1,429 | 8.2 | 9 | 11.4 | 12 |
| 40 x 50 ft, 1 storey | 2,000 | 1,952 | 11.2 | 12 | 15.6 | 16 |
| 40 x 60 ft, 1 storey | 2,400 | 2,106 | 12 | 13 | 16.8 | 17 |
| 26 x 36 ft, 2 storey | 1,872 | 2,401 | 13.7 | 14 | 19.2 | 20 |
| 30 x 40 ft, 2 storey | 2,400 | 2,726 | 15.6 | 16 | 21.8 | 22 |
| 34 x 44 ft, 2 storey | 2,992 | 3,038 | 17.4 | 18 | 24.3 | 25 |
One coat, for a same-colour recoat
| House | Smooth (gal) | Buy | Rough (gal) | Buy |
|---|---|---|---|---|
| 24 x 40 ft, 1 storey | 3.6 | 4 | 5 | 6 |
| 30 x 40 ft, 1 storey | 4.1 | 5 | 5.7 | 6 |
| 40 x 50 ft, 1 storey | 5.6 | 6 | 7.8 | 8 |
| 40 x 60 ft, 1 storey | 6 | 7 | 8.4 | 9 |
| 26 x 36 ft, 2 storey | 6.9 | 7 | 9.6 | 10 |
| 30 x 40 ft, 2 storey | 7.8 | 8 | 10.9 | 11 |
| 34 x 44 ft, 2 storey | 8.7 | 9 | 12.2 | 13 |
Trim, fascia and soffit
Casings at 4 inches wide around every door and window, plus a 6 inch fascia and a 12 inch soffit along the whole eave line, painted twice at 350 sq ft per gallon. Buy trim paint in gallons; quarts run out mid-window.
| House | Trim area (sq ft) | Gallons | Buy |
|---|---|---|---|
| 24 x 40 ft, 1 storey | 250 | 1.4 | 2 |
| 30 x 40 ft, 1 storey | 277 | 1.6 | 2 |
| 40 x 50 ft, 1 storey | 356 | 2 | 3 |
| 40 x 60 ft, 1 storey | 401 | 2.3 | 3 |
| 26 x 36 ft, 2 storey | 272 | 1.6 | 2 |
| 30 x 40 ft, 2 storey | 315 | 1.8 | 2 |
| 34 x 44 ft, 2 storey | 363 | 2.1 | 3 |
How the numbers are worked out
For the 30 x 40 ft ranch: perimeter 140 ft x 10 ft = 1,400 sq ft of wall, plus two gables of 30 x 7.5 / 2 = 225 sq ft, minus 2 doors and 12 windows (196 sq ft) = 1,429 sq ft. Times two coats, divided by 350 = 8.17 gallons, rounded up to whole cans. A hip roof has no gables, so drop that line; a wrap-around porch adds its ceiling and columns. The paint calculator takes any net area and the coverage on your can, and the coverage guide explains why rough surfaces take more.
Buying and planning
- Over about 6 gallons buy 5 gallon pails; box (mix) all of them together before you start so the colour is identical on every wall.
- Bare wood, chalky old paint and fibre cement need a primer coat at about the same coverage as the paint; it is not in the tables.
- Add 10% if you are spraying, and keep a gallon back for touch-ups after the gutters go up.
- Fences and decks are separate jobs with their own coverage; the fence stain guide has those tables.
Metric: 8 x 10 to 10 x 14 m houses
3 m per storey, gables at the same pitch, doors and windows deducted at 1.9 and 1.2 m². Two coats at 10 m² per litre on smooth render or timber and 7 on rough render or bare masonry, bought in 10 L tins.
| House | Wall to paint (m²) | Smooth (L) | Tins | Rough (L) | Tins |
|---|---|---|---|---|---|
| 8 x 12 m, 1 storey | 120 | 24 | 3 | 34.3 | 4 |
| 10 x 14 m, 1 storey | 148 | 29.7 | 3 | 42.4 | 5 |
| 8 x 10 m, 2 storey | 211 | 42.3 | 5 | 60.4 | 7 |
| 10 x 12 m, 2 storey | 264 | 52.7 | 6 | 75.3 | 8 |
Larger houses and the 2,106 sq ft of a 40 x 60 ft ranch are in the imperial table above; the arithmetic is the same in either system.
Frequently asked questions
- How many gallons of exterior paint for a 2,000 sq ft house?
- 12 to 20 gallons, depending on the shape of the house and the siding, not just the floor area. A single-storey 40 x 50 ft house (2,000 sq ft) has about 1,952 sq ft of siding and takes 12 gallons for two coats on smooth siding or 16 on rough; a two-storey 26 x 36 ft house (1,872 sq ft of floor) has 2,401 sq ft of wall and takes 14 or 20. Measure the perimeter and the height; the floor area only hints.
- How much paint for the exterior of a 2 storey house?
- 16 gallons for a 30 x 40 ft two-storey with 20 windows on smooth siding at two coats (2,726 sq ft), 22 on rough. A larger 34 x 44 ft two-storey is 18 or 25 gallons. Buy in 5 gallon pails once you are past about 6 gallons; they are cheaper per gallon and the colour is one batch.
- How many square feet does a gallon of exterior paint cover?
- Most labels say 250 to 400 sq ft per gallon per coat. This page uses 350 for smooth or previously painted siding and 250 for rough sawn wood, stucco, brick and bare fibre cement, which drink the first coat. Spraying uses 20 to 30% more than brushing; use the figure on your can in the calculator.
- Do I need two coats of exterior paint?
- Two coats over a primed or previously painted surface in a similar colour is the standard; one coat is acceptable for a maintenance recoat in the same colour on sound paint. A dark-to-light change or bare wood needs primer plus two coats. The difference on the 30 x 40 ft ranch is 5 gallons against 9, so the second coat is not where to save.
- How much trim paint for a house exterior?
- About 2 gallons for two coats on a 30 x 40 ft ranch, 2 on a 30 x 40 ft two-storey. Casings on 2 doors and 12 windows at 4 inches wide plus a 6 inch fascia and 12 inch soffit around the eaves come to about 277 sq ft on the ranch, 1.6 gallons rounded up. Trim is a small area but a lot of edges; shutters, railings and a porch ceiling are on top of that.
- How do I measure my house for exterior paint?
- Walk the perimeter with a tape (or add the sides from the plans), multiply by the wall height from the foundation to the eaves for each storey, add the two gable triangles (width x rise / 2 each) if the roof has gables, then subtract about 20 sq ft per door and 13 sq ft per window. Enter that net area in the paint calculator with the coverage on your can.
More guides
- How much paint do I need for a 12x12 room?
Gallons of paint for a 12 x 12 ft room with 8, 9 or 10 ft ceilings, one or two coats, a door and two windows deducted, plus the 4 x 4 m room in litres.
- How many square feet does a gallon of paint cover?
A gallon covers about 350 to 400 sq ft on smooth walls, less on rough or bare surfaces. Gallons for 400 to 2,000 sq ft at one and two coats, and litres per square metre.
- How much paint do I need for a ceiling?
Quarts and gallons of ceiling paint for 10x10, 12x12, 15x15 and 20x20 ft ceilings at one and two coats, plus 3x3 to 5x5 m ceilings in litres.
- How much paint for a 10x10 room? (10x12, 12x14 and 14x16 too)
Gallons of paint for a 10x10 room with an 8 ft ceiling, a door and two windows, one or two coats, plus the ceiling; 10x12 to 14x16 rooms; 3x3 to 4x5 m rooms in litres.
Last updated 2026-09-13. Figures are planning estimates from typical product data: check the yield, size or coverage printed on what you buy and round up.