This paint calculator works out how much paint a room needs from its dimensions, doors, windows, number of coats and the coverage on the can.
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With 8 ft walls, one door, two windows and two coats at 350 sq ft per gallon, you need about 2.09 gal including 10% extra. Buy 2.25 gallons.
Paint to buy
2.5 gallons
Inputs
Results are estimates for planning only. Supplier specifications, product yields, site conditions and local codes vary. Confirm quantities with your supplier or a qualified professional before you buy or build.
room length 14 ft, room width 12 ft, wall height 8 ft, doors 1 pcs, windows 2 pcs, Walls only, coats 2 coats, paint coverage 350 ft²/gal.
Paint to buy
2.5 gallons
room length 4.2 m, room width 3.6 m, wall height 2.4 m, doors 1 pcs, windows 2 pcs, Walls + ceiling, coats 2 coats, paint coverage 10 m²/L.
Paint to buy
11 litres
room length 18 ft, room width 14 ft, wall height 9 ft, doors 2 pcs, windows 3 pcs, Walls only, coats 2 coats, paint coverage 350 ft²/gal.
Paint to buy
3.25 gallons
room length 8 ft, room width 6 ft, wall height 8 ft, doors 1 pcs, windows 1 pcs, Walls + ceiling, coats 2 coats, paint coverage 350 ft²/gal.
Paint to buy
1.5 gallons
8 ft walls, one door, two windows, walls only, two coats at 350 sq ft per gallon, 10% waste.
| Room size | Paintable wall area | Paint to buy |
|---|---|---|
| 10 × 10 ft | 268.9 ft² | 1.75 gallons |
| 12 × 12 ft | 332.9 ft² | 2.25 gallons |
| 12 × 14 ft | 364.9 ft² | 2.5 gallons |
| 14 × 16 ft | 428.9 ft² | 2.75 gallons |
| 16 × 20 ft | 524.9 ft² | 3.5 gallons |
Coverage figures on the can assume a smooth, primed surface. Rough plaster, bare drywall, brick and dark colours being covered by light ones all use more paint, which is why you should round up and why two coats are the default.
Buying a little more than the minimum is cheap insurance. Matching a colour later from a different batch can be difficult, and leftover paint is handy for touch-ups. Refreshing the floor too? Use the flooring calculator or the tile calculator.
Preparation affects how much paint you use. Clean walls, fill and sand holes, and prime bare patches. Porous surfaces such as new drywall soak up paint on the first coat, and a primer or a first coat of diluted paint can reduce that. Check the can for guidance.
Ceilings usually take flat paint and walls a different finish, so they are bought separately. Run the calculator once with walls only and again for the ceiling alone if you are using two paints. Trim, door frames and window frames are small areas but need their own paint.
Many manufacturers state around 350–400 square feet per gallon on smooth, primed surfaces. Use the figure on your can for the best result.
Two coats is standard for an even finish. A single coat may be enough when repainting a similar colour with a quality paint, but check the product label.
Yes, for large openings. The calculator subtracts a standard size for each door and window you enter.
Often, on bare drywall, stains, or when changing from a dark to a light colour. Primer is a separate product, so calculate it with the same area and the coverage on the primer can.
With 8 ft walls, one door, two windows, two coats and 10% waste, about 2.1 gallons. Round up to 2.25 gallons, or buy a 2-gallon and a 1-quart can.
Yes. Rough or porous surfaces soak up more paint, so use a lower coverage figure than the can states, such as 250–300 sq ft per gallon.
A 12 × 8 ft wall is 96 square feet. Two coats is 192 square feet, which at 350 square feet per gallon is about 0.55 gallon, or 0.6 with 10% extra. A 1-gallon can covers it with room to spare, or buy 3 quarts.
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Get the embed codeResults are estimates for planning only. Supplier specifications, product yields, site conditions and local codes vary. Confirm quantities with your supplier or a qualified professional before you buy or build.