Free tool · Takeoff
Paint Coverage Calculator
Enter the length, width and ceiling height of each room, with its doors and windows, and the calculator works out the wall and ceiling areas and the gallons of paint to buy. Set the number of coats and the coverage printed on the can, and add primer if you need it.
The numbers stay in your browser: we do not store or receive them.
Rooms
What you are painting
Wall paint
3 gal
365 sq ft, 2 coats
Ceiling paint
2 gal
168 sq ft, 2 coats
Includes 10.0% waste, rounded up to whole gallons for each paint. 51 sq ft of doors and windows are taken off the walls.
| Room | Wall (sq ft) | Doors and windows | Ceiling (sq ft) |
|---|---|---|---|
| Living room | 365 | −51 | 168 |
How the area is figured
Walls = 2 × (length + width) × ceiling height, less the doors and windows. The calculator takes off 21 sq ft for a standard 3 ft by 7 ft door and 15 sq ft for an average window, and you can change both.
Ceiling = length × width.
Gallons = area × coats ÷ coverage, plus waste, rounded up to a whole gallon. Walls and ceilings are figured separately because they are often different paint, and primer is figured on the whole painted area.
A worked example
A 12 ft by 14 ft room with 8 ft ceilings has 416 sq ft of wall. One door and two windows take off 51 sq ft, which leaves 365 sq ft. The ceiling is 168 sq ft.
At two coats and 350 sq ft per gallon with 10 percent waste, the walls take 365 × 2 ÷ 350 × 1.1 = 2.3 gallons, so 3 gallons. The ceiling takes 1.06 gallons, so 2 gallons.
Coverage, coats and waste
The coverage on the can is for a smooth, sealed surface. Rough, textured or porous surfaces such as new drywall, raw wood or block soak up more, and a dark color over a light one may need an extra coat. Use a lower coverage number for those. Waste covers cutting in, rollers and trays, touch-ups and spills; 10 percent is a common allowance and the box is yours to change.
What this does not do
It does not figure trim, baseboards, crown, doors, windows, cabinets or stairs, so add those separately. It does not account for sloped or vaulted ceilings or gables, so enter those as an equivalent room or add the extra area by hand. Always check the coverage and the coats on the paint you buy.
FAQ
How much paint do I need for a room?
Figure the wall area, take off doors and windows, then divide the area times the number of coats by the coverage per gallon. For a 12 by 14 ft room with 8 ft ceilings that is about 3 gallons of wall paint for two coats.
How many square feet does a gallon cover?
The can states it, often around 350 to 400 sq ft for one coat on a smooth surface. Enter the number on your can, and use a lower number for rough or porous surfaces.
Do I need primer?
New drywall, bare wood, stains and big color changes usually do. Set the primer coats to 1 and enter the primer’s coverage from its can.
Why does it round up to whole gallons?
Paint is sold by the gallon, and running out partway through a wall can leave a visible color difference between batches. Rounding up each paint keeps you covered.
Should the ceiling use the same paint as the walls?
Often not, since ceilings usually get a flat white. That is why wall and ceiling gallons are shown separately. You can also turn either one off.
Is anything I type saved?
No. The calculation runs in your browser and nothing is stored or sent to us.
Pricing the whole job? PoPs Estimating measures walls, ceilings and finishes from your plans and keeps the quantities tied to the bid.
Questions?
Ask us anything about PoPs Suite, pricing, or running a construction company. A real person answers, usually within a business day.