Paint calculator
Enter the total wall length and height, the doors and windows, the finish and the number of coats to get the gallons of paint to buy. Free, no signup.
Paint for a room
Part of Foster Tools: 7 pro calculators in one appOpen in app →Paint questions
How much paint do I need for a room?
Multiply the total wall length by the wall height, subtract about 21 square feet per door and 15 per window, then divide by the coverage per gallon and multiply by the number of coats. A 12 by 12 foot room with 8 foot walls, one door and two windows has about 333 square feet to paint; two coats of eggshell take about 1.75 gallons, so buy 2.
How many square feet does a gallon of paint cover?
About 350 to 400 square feet per coat on smooth walls. Glossier finishes and textured walls cover less, so you need a little more paint.
Do I need primer?
Use primer on new drywall, bare wood, stains and patches, and when you’re covering a dark colour with a light one. Repainting a similar colour over sound paint usually doesn’t need it.
How many coats of paint should I use?
Two coats is the standard for an even finish. One coat can be enough when you’re refreshing the same colour; strong colour changes may need three.
Does the calculator include the ceiling?
No, it calculates the walls. For a ceiling, enter the ceiling’s length and width as wall length and height, or use the Ceiling surface in Pro.
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