US gallons. Purchase quantity is rounded up to full gallons; confirm available package sizes and the product's coverage before ordering.
How the paint estimate is calculated
Choose Room dimensions for a rectangular room. Length and width determine the perimeter; ceiling height determines the wall area. The quick estimate deducts 21 ft² for each door and 15 ft² for each window. These are estimating assumptions, not measurements of your openings.
If Include ceiling is selected, the calculator adds length × width. Combine walls and ceiling only when they use the same paint product, color, finish and coat count. Otherwise calculate each separately.
Choose Paintable surface area when you already know the area to paint. Add the measured surfaces and deduct unpainted openings before entering the number. This mode does not add a ceiling or deduct doors and windows.
Paint needed = paintable surface area × coats ÷ coverage per US gallon
The result rounds up to whole gallons for purchasing. Estimated cost equals that rounded quantity multiplied by your entered price per gallon. No separate waste or touch-up percentage is applied.
How many gallons of paint for 1,000 sq ft?
For 1,000 ft² of actual paintable surface, two coats and coverage of 350 ft² per gallon per coat:
Total coat area: 1,000 × 2 = 2,000 ft².
Calculated paint: 2,000 ÷ 350 = 5.71 US gallons.
Whole-gallon purchase: round up to 6 US gallons.
At an example price of $40 per gallon, the estimated paint cost is 6 × $40 = $240. This price is illustrative; enter your local product price for your estimate. The example excludes primer, supplies, tax and labor, and adds no separate reserve.
Is that the same as a 1,000 sq ft house?
No. A home's listed square footage usually describes floor area. It does not tell you the wall perimeter, ceiling height, number of partitions or openings. For a 1,000 sq ft home, measure each room's walls and any ceilings you plan to paint. Combine net surface areas only for surfaces using the same product and coat count.
For the calculator's default 12 × 14 ft room with 8 ft ceilings, one door and two windows, the walls are 365 ft² after deductions. Including the 168 ft² ceiling gives 533 ft². At two coats and 350 ft² per gallon, that is 3.05 gallons calculated and 4 whole gallons to buy.
Turn the estimate into a paint purchase
Check coverage and coat recommendations for the exact product and surface. Absorbent or textured surfaces and application methods can affect how much paint you use. For example, Sherwin-Williams' estimating guidance discusses variation by surface and application. A specific Benjamin Moore ben interior matte product lists its own coverage and coat recommendations. Neither brand has one coverage rate that applies to every product.
For a 6-gallon purchase, compare six 1-gallon cans with a 5-gallon pail plus one 1-gallon can, where those sizes are available in the same product, color and finish. Compare actual package prices; this calculator's single price-per-gallon field does not identify the cheapest package combination.
Decide how much extra you need for touch-ups or application loss. Rounding can leave some paint, but it is not a guaranteed reserve. Estimate primer separately using its own coverage and coat instructions.