Free paint coverage calculator. Enter wall area and coats to find the paint in litres and the 5 litre cans you need for the walls.
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Enter wall area in square metres and the number of coats. This calculator allows 10 square metres per litre per coat, and divides the total litres by 5 litres per can to give the can count.
Paint coverage per litre in this calculator is 10 square metres per litre per coat, for smooth, primed walls. The formula is paint litres equals wall area times coats divided by 10. For 20 square metres and 2 coats, that gives 4.0 litres and 0.8 cans of 5 litres. For 10 square metres and 1 coat, it gives 1.0 litre and 0.2 cans. Competitor guides quote about 8.6 square metres per litre for 350 square feet per gallon and about 9.8 square metres per litre for 400 square feet per gallon, so 10 square metres per litre is a planning figure for smooth walls, and rough or unprimed walls need more.
How many coats paint wall needs depends on the colour change. A same colour refresh may need only 1 coat, a standard colour change needs 2 coats, light over dark needs 2 to 3 coats plus primer, and new drywall needs primer plus 2 coats. Paint primer litres use a lower coverage than topcoat, about 200 to 300 square feet per gallon, so plan primer separately and do not count it as a topcoat. Primer does not replace a coat of paint, it helps the topcoat cover evenly and stick properly, especially on bare drywall and dark colours.
Paint doors windows subtract is the step most beginners skip. Measure wall area as perimeter times ceiling height, then subtract openings: a standard interior door is about 18 to 21 square feet, a wide or exterior door about 20 square feet, a standard window about 12 to 15 square feet, and a large or picture window about 20 square feet. For a 12 by 12 foot room with 8 foot ceilings, wall area is 384 square feet, minus 1 door and 2 windows at about 51 square feet, giving about 333 square feet net. Enter the net area in this calculator, not the gross wall area.
Paint for a room calculator examples using this formula: a 10 by 10 foot room with 8 foot ceilings has about 320 square feet of wall, or about 30 square metres gross, and about 26 square metres net after openings, so 2 coats need about 5.2 litres. A paint 12x12 room has about 384 square feet of wall, or about 36 square metres gross, and about 31 square metres net, so 2 coats need about 6.2 litres, or about 1.2 cans of 5 litres, rounded up to 2 cans. A 16 by 20 foot room has about 576 square feet of wall, or about 54 square metres gross, and about 49 square metres net, so 2 coats need about 9.8 litres, or about 2 cans.
Paint ceiling litres are calculated the same way, but ceiling area is length times width, not perimeter times height. A 12 by 12 foot ceiling is 144 square feet, or about 13.4 square metres, so 1 coat needs about 1.3 litres and 2 coats need about 2.7 litres at 10 square metres per litre. Trim area is small but fiddly: measure trim length times about 0.5 feet width, and plan about 1 quart for a typical room of trim, doors, and windows combined. Paint ceilings, trim, and walls as separate calculations, since they often use different finishes and coats.
Paint textured wall coverage is lower than smooth wall coverage. Smooth, previously painted walls cover at about 350 to 400 square feet per gallon. New drywall without primer covers at about 250 to 300 square feet per gallon. Textured orange peel or knockdown covers at about 200 to 300 square feet per gallon. Rough masonry, brick, or stucco covers at about 150 to 250 square feet per gallon. As a rule, reduce coverage by 10 to 20 percent for new or unprimed drywall, by 20 to 30 percent for porous masonry or raw plaster, and by 20 to 30 percent for textured surfaces, or up to 50 percent for heavy texture or popcorn.
Paint sheen coverage flat eggshell and other finishes differ slightly, but sheen matters more for room choice than for quantity. Flat and matte finishes cover about 400 square feet per gallon and suit ceilings and low traffic rooms. Eggshell covers about 350 square feet per gallon and suits living rooms and dining rooms. Satin covers about 350 square feet per gallon and suits bedrooms and hallways. Semi gloss covers about 300 square feet per gallon and suits kitchens, bathrooms, and trim. High gloss suits cabinets and doors. Sheen does not change the formula, but it changes the finish you buy.
Paint waste factor buy extra is the safety margin that stops you running out halfway through a wall. Allow 10 to 15 percent extra for touch ups, plus 5 to 10 percent waste for brush and roller work, or 20 to 30 percent waste for spray work, since overspray loses paint. Buy the next whole can up when the result is fractional: 0.8 cans means buy 1 can, and 1.2 cans means buy 2 cans, keeping the same batch for colour matching. Paint gallons per room conversion: 1 litre is about 0.264 US gallons, 1 US gallon is about 3.785 litres, and 350 square feet per gallon is about 8.6 square metres per litre.
About 10 square metres per litre per coat in this calculator, for smooth, primed walls. Rough, textured, or unprimed walls cover less, about 6 to 8 square metres per litre.
One coat for a same colour refresh, 2 coats for a standard colour change, and 2 to 3 coats plus primer for light over dark or new drywall.
About 400 square feet per gallon for flat paint on smooth walls, and about 350 square feet per gallon for eggshell or satin. Textured and masonry surfaces cover much less.
Yes for new drywall, dark colours, and bare surfaces. Plan primer separately at about 200 to 300 square feet per gallon, since primer does not replace a topcoat.
Yes. Subtract about 18 to 21 square feet per door and about 12 to 15 square feet per standard window from the gross wall area before calculating paint.
About 31 square metres net wall area, so 2 coats need about 6.2 litres at 10 square metres per litre, rounded up to 2 cans of 5 litres.
Ceiling area is length times width. A 12 by 12 foot ceiling is about 13.4 square metres, so 2 coats need about 2.7 litres at 10 square metres per litre.
Slightly. Flat covers about 400 square feet per gallon, eggshell and satin about 350, and semi gloss about 300. Choose sheen by room use, not just coverage.
Yes. Allow 10 to 15 percent extra for touch ups, plus waste for your application method, and round up to whole cans from the same batch for colour matching.
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