1st Step: Calculate Height
Measure the height from the bottom of the baseboard to the ceiling.
2nd Step: Calculate Length and Width
Measure the Length of two walls and add them together. Ideally, start from the left and work to the right. Once you finish adding the walls, you will multiply by 2 (We multiply by 2 because this is the number of walls left to measure, in the beginning, we added 2 walls. (This only works for a room with 4 walls.)Â
3rd Step: Calculate Paint Need For Walls
Multiple the Height x Length.Â
4th Step: Calculate Paint Need For Ceilings
If you are painting the ceiling, keep reading. Now multiply the length x width.Â
5th Step:Â Total Paint Gallons NeededÂ
Add Total Walls (Step 3) + Total Ceiling (Step 4), then divide by 400.Â