Paint calculator
Paint Calculator — Gallons by Surface and Coats (2026)
How many gallons of paint do I need? Calculates paint (and optional primer) for smooth, textured, and porous surfaces. Inputs wall area or room dimensions, subtracts windows and doors, and chooses coat count (1-5). Mobile-friendly.
Pricing
Enter wall area (or room dimensions) above to see how much paint you need.
Paint & primer on Amazon
Stock the rollers, brush, and tape the calculator above can't measure — gallons come straight from the paint calculator result.
- Interior latex paint (1 gallon) ↗
Pick sheen to match the surface — eggshell for living areas, flat for ceilings.
- Multi-surface primer (1 gallon) ↗
Half a gallon per top-coat gallon for color changes and bare drywall.
- 9 in × 3/8 in nap roller cover (pack) ↗
Smooth drywall — switch to 1/2 in nap for textured walls.
- 9 in roller frame ↗
Standard size; pair with a threaded extension pole below.
- Threaded extension pole (4 ft) ↗
Roll ceilings and tall walls without a ladder.
- 2-1/2 in angled sash brush ↗
Cut in edges and trim — keep one dedicated to water-based paint.
- Painters tape (1.5 in × 60 yd) ↗
Pull tape while the paint is still slightly tacky for clean edges.
Amazon links may earn Pour Tech a small commission at no extra cost to you — see our Affiliate Disclosure.
Related calculators
- Drywall calculator
Sheets, mud, tape, screws, and corner bead per room.
- Concrete calculator
How much concrete for slab, post hole, footing, or column.
- Studs calculator
Stud count and top/bottom plate linear feet for the same wall.