Interior Painting Estimating: How to Price Any Paint Job Accurately

Start with Paintable Square Footage

Paintable square footage is NOT the same as floor square footage.

Calculate wall area: Perimeter of room × ceiling height. Subtract openings:

Standard door: 21 sqft

Standard window: 15 sqft

Do NOT subtract if painting the room with the door open — some painters include the door reveal

Ceiling area: Length × width (if painting ceilings — confirm with client)

Standard interior paint covers 350–400 sqft per gallon for smooth surfaces. Reduce to 300–350 sqft for:

Textured walls (orange peel, knockdown)

Porous surfaces (new drywall, bare wood)

Dark to light color changes (may need extra coat)

Number of coats:

Same or similar color: 2 coats typical

Dark to light change: 3 coats (sometimes 4)

New drywall: 1 coat primer + 2 coats finish

Trim and doors are often priced separately:

Linear feet of baseboard/crown/casing: Measure and price at $1.50–$3.00/LF painted

Interior doors: $50–$150 each painted (both sides)

Window trim: $40–$100 per window

Prep (taping, patching, sanding): $0.30–$0.60/sqft

Painting walls: $0.75–$1.50/sqft (2 coats)

High ceilings (10+ feet): Add 25–40% to labor for scaffolding/ladders

Painting ceilings: $1.00–$2.00/sqft (harder than walls)