How much exterior paint for a 40×28 ft 1-story house?

A 40×28 ft 1-story house with two gable ends has about 1,146 sq ft of paintable siding after doors, 8 windows and a garage door. Two coats at 300 sq ft per gallon take 7.6 gallons — buy 8 gallons. One coat takes about 4 gallons.

Change the numbers

The calculator below is pre-filled for this project. Adjust any value — including feet and inches — and the results update instantly.

Gables are measured across the house width. Trim, doors and shutters usually take a separate quart or gallon of trim paint.

Your results

Exterior paint to buy8 gallons

As packaged1 five-gallon bucket + 3 gallons

Paintable area1,146 sq ft

Exact paint (2 coats)7.64 gal

Walls + gables1,224 + 196 sq ft

Doors & windows subtracted274 sq ft

Primer, if needed (1 coat)4 gallons

How much exterior paint for a 40×28 ft 1-story house — diagram

Gallons by siding type (2 coats)

Coverage	Exact gallons	Buy	As packaged
400 sq ft/gal	5.7	6 gallons	1 × 5 gal + 1 × 1 gal
350 sq ft/gal	6.5	7 gallons	1 × 5 gal + 2 × 1 gal
300 sq ft/gal	7.6	8 gallons	1 × 5 gal + 3 × 1 gal
250 sq ft/gal	9.2	10 gallons	2 × 5 gal

Where the area comes from

Walls: 2 × (40 + 28) × 9 ft × 1 = 1,224 sq ft
Two gables at a 6/12 pitch: 196 sq ft
Openings subtracted: 274 sq ft

Measure your own house — porches, bump-outs and dormers change the total. Trim usually needs another 1–2 gallons of trim paint.

Common questions

How many gallons of paint for a 40x28 1-story house?

About 8 gallons for two coats on 1,146 sq ft of siding at 300 sq ft per gallon.

Want the full method, tips and other sizes? See the exterior paint calculator guide.

Last reviewed November 1, 2026. Results are estimates — confirm with your supplier.

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