Paint Calculator
Free paint calculator — how much paint to buy for a room from wall dimensions, coats, and coverage, in litres or gallons, with an animated wall.
Everyday Uses
Room makeovers
Buy the right amount of paint for a bedroom, hallway, or whole house.
Budgeting
Estimate cans and cost before you get to the store, no guesswork.
Openings subtracted
Account for doors and windows so you don't over-buy paint.
Coats
See how a second or third coat changes the total you need.
Frequently Asked Questions
How much paint do I need for a room?
First find the wall area: add up the length of every wall and multiply by the height (for a rectangular room, area = 2 × (length + width) × height). Subtract about 1.8 m² (20 ft²) for each door and window. Then divide by the paint's coverage (around 10 m² per litre, or 350 ft² per gallon) and multiply by the number of coats. A 4 × 3 m room with 2.4 m walls needs roughly 6 litres for two coats.
How much does one litre or gallon of paint cover?
A litre of paint typically covers about 10–12 m²; a US gallon covers about 350–400 ft² per coat. Rough or porous surfaces and strong colour changes absorb more, so the first coat often covers less than the second. Always check the coverage printed on your specific tin.
How many coats of paint do I need?
Two coats is standard for a durable, even finish. You may need three when painting a light colour over a dark one, covering stains, or using a thin or budget paint. A tinted primer can reduce the number of top coats needed.