How much paint does a room need?
Add up the wall area (perimeter × height), subtract doors and windows, and multiply by the number of coats. Divide by the coverage on the tin. A gallon typically covers 350–400 sq ft, a liter about 10 m² on smooth, primed walls.
How many coats?
Two coats is the standard for an even finish. One coat can be enough when repainting the same colour. Going from dark to light, or painting fresh plaster, usually needs a primer plus two coats.
Tips
- Buy all the paint for one room at once so the colour matches.
- Rough surfaces like brick or textured plaster can use 20–50% more paint.
- Keep a little left over for touch-ups.