What affects coverage
Paint coverage varies by surface texture, primer, paint type, color change and application method. Use the coverage printed on the product label when available.
Example
For 500 square feet, 2 coats and 350 square feet of coverage per unit, the base estimate is 500 x 2 / 350 = 2.86 units. With 10% waste, that becomes 3.14 units, so you would usually buy 4 full units if the store sells only whole cans.
Common mistakes
Do not forget ceilings, trim or second coats if they are part of the job. If you already measured wall area before subtracting windows and doors, the estimate may be high.
Limitations
This estimate does not subtract windows and doors unless you already removed them from area. Real purchases are rounded to package sizes, and rough surfaces may need more paint than the label average.
Last reviewed: 2026-05-17