Paint Calculator

Wall area (minus doors/windows) × number of coats, divided by the paint's coverage rate (typically ~350 sq ft per gallon), plus a waste allowance for roller loss and touch-ups.

A standard door is about 19 sq ft and a standard window about 15 sq ft of unpainted area — both are subtracted from the gross wall area.

Two coats is standard for most walls. A single coat rarely gives even coverage or true color, especially over a different existing color.

Bare drywall, patched areas, or a strong color change (especially going lighter over darker) usually needs one priming coat before the color coats.