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Paint Calculator

Figure out how many gallons of paint to buy for any room — walls, ceiling, doors and windows subtracted, multiple coats, primer, U.S. pricing, and a downloadable PDF material list.

Coverage varies by paint, color change, and surface — always check the can (usually 350-400 sq ft/gal). Dark-to-light changes may need an extra coat. For planning purposes only.

Room, Coats & Paint
1 Area to Paint
ft
×
ft
ft
Standard is 8 ft; older homes often 9-10 ft
sq ft
Walls = 2 × (length + width) × height
Adds length × width to the paintable area
doors
+
wins
Auto-subtracts ~21 sq ft per door and ~15 sq ft per window
sq ft
2 Coats & Coverage
Bare drywall soaks up paint — a primer coat is recommended and has been switched on.
sq ft/gal
Check the can — most interior paint lists 350-400 sq ft/gal
3 Paint & Cost
10%
~10% covers touch-ups and cut-in; bump up for many corners or spraying
$/ gallon
sq ft/gal
Primer is 1 coat; covers less than paint (~200-350 sq ft/gal)
$/ gallon
$flat
Rollers, tray, brushes, tape, drop cloths — set 0 to skip
$/ sq ft
Set 0 for DIY / materials only
Paint Estimate
Gallons To Buy
—
Enter your room to begin
Paint (gallons, with waste) —
Total paint area —
Coverage / Gallon —
Full Cost Breakdown
Paintable area —
Paint —
TOTAL ESTIMATE—
Total cost / sq ft —
Net wall + ceiling —
Primer gallons —
Cost Breakdown Chart
Estimated cost by category ($)
Coats Comparison — Your Room
CoatsPaint AreaGallonsPaint CostCost / sq ft

For your 333 sq ft of paintable surface. More coats = more gallons and better color depth.