Interior
Paint Calculator
Estimate paint by wall dimensions, coats, and coverage. Doors and windows are subtracted automatically.
Inputs
Live estimate
Gallons needed
2
- Gross wall area
- 384 sq ft
- Paintable area
- 333 sq ft
Live estimate
- Mathematical quantity
- 2
- Coverage variation by surface
- Informational
- Field conditions
- Not applied
- Adjusted requirement
- 2
- Ordering rule
- Round up to whole gallon
- Suggested order
- 2
Rough, textured, or freshly-primed surfaces absorb noticeably more paint than the label coverage.
What you actually need in the field, before rounding to a supplier-friendly ordering unit.
Estimator confidence
HighRough, textured, or freshly-primed surfaces absorb noticeably more paint than the label coverage.
- Surface texture — Smooth drywall covers to the label; stucco can consume 2× the paint.
- Coat count — Primer + two coats is different from two-coat repainting.
- Prime new drywall separately — don't skip it just because the paint says self-priming.
- Buy paint from one batch to avoid subtle color shifts between gallons.
- Save one quart of finish paint for touch-ups.
- Assuming spec-sheet coverage on textured or porous walls.
- Skipping primer on new drywall.
- Under-buying deep colors and running short on the second coat.
Smart tips
- Ordering 5–10% extra is standard on irregular layouts. Running short costs more than the excess.
How it's calculated
Gross area = walls × wall length × wall height.
Paintable area = gross area − (doors × 21) − (windows × 15).
Gallons = ceil(paintable × coats ÷ coverage × (1 + waste %)).
Material assumptions
- Standard coverage: 350 sq ft per gallon per coat.
- Doors subtract 21 sq ft each; windows subtract 15 sq ft each.
- Add 5–10% for touch-ups on textured or new drywall.
Frequently asked questions
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These results are estimates only. Confirm quantities, compaction, waste, and delivery requirements with your supplier or project professional before ordering materials.