How Much Paint for a 500 Sq Ft Accent Wall and Stairwell
A 500 sq ft accent wall or open two-story stairwell wall requires 1.43 gallons of paint per coat at 350 sq ft/gal coverage. For two complete coats (1,000 sq ft total surface area), you need 2.85 gallons. Therefore, you must purchase exactly 3 gallons of interior paint.
Published 2026-03-01 · Updated 2026-03-01 · 8 min read
Calculating Complex Stairwell Wall Geometry
Two-story stairwells are rarely simple rectangles. To measure accurately, divide the wall into two geometric shapes: a lower right triangle following the staircase incline, and an upper rectangle extending to the ceiling. Sum these two areas together.
Worked Example: 2-Story Foyer Stairwell (500 sq ft wall)
Painting an open 18-foot tall stairwell wall in deep charcoal satin paint with 2 coats.
Purchase 3 gallons of paint. Keep the remaining 0.15 gallons in an airtight mason jar for high-reach scuff repairs.
Do deep dark accent colors need more than 2 coats?
Using a gray-tinted primer (such as P-4 or P-5 gray) allows vibrant navy, emerald, or charcoal colors to achieve full opacity in just 2 finish coats.
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