Interior Painting Cost Calculator
Updated · By the CalculatorDash editorial team · How we check our maths
Quick answer
Professional interior painting typically costs $2–$6 per square foot of floor area, or about $2,000–$6,000 per 1,000 sq ft, depending on whether ceilings and trim are included. Labor is most of the cost; paint itself is usually $25–$45 a gallon and one gallon covers roughly 350–400 sq ft per coat.
How this calculator works
Painters quote by the paintable surface, not the floor plan, but most homeowners only know their floor area. This calculator converts floor area into an approximate wall area (about 2.7 sq ft of wall per sq ft of floor at an 8-foot ceiling, scaled for taller rooms), adds ceilings if selected, and prices labor and paint separately.
Coats and prep drive the labor number. A same-colour refresh might need one coat; a colour change usually needs two; going from a dark colour to a light one can take three. Heavy prep, such as patching cracks or removing wallpaper, can add a third to the labor.
The formula
- Wall area
- floor area × (ceiling height ÷ 8) × 2.7
- Paint gallons
- round up(surface × coats ÷ 375 × 1.1)
- Materials
- gallons × price per gallon × 1.25
- Labor
- surface × labor rate × prep multiplier × coat factor
Worked example
For 1,200 sq ft of floor with 8-foot ceilings and two coats, wall area is about 3,240 sq ft. That needs 3,240 × 2 ÷ 375 × 1.1 ≈ 20 gallons. At $40 a gallon plus supplies, materials come to $1,000. Labor at $1.60 per sq ft is $5,184, for a total near $6,200.
Tips
- 01Walk every room before giving a firm price; trim, doors and repairs change the job a lot.
- 02Sell premium paint as an upgrade. Better coverage can save a coat, which saves you labor.
- 03Charge accent walls and colour changes per room so the base quote stays competitive.
Frequently asked questions
How much does it cost to paint a room?
A typical 12 × 12 ft bedroom has around 400 sq ft of wall. With two coats at common labor rates, expect a few hundred dollars to around $1,000 depending on ceilings, trim and region.
How many gallons of paint do I need?
One gallon covers about 350–400 sq ft per coat on smooth walls. Multiply your wall area by the number of coats, divide by 375 and add about 10% for touch-ups.
Is painting priced by floor area or wall area?
Contractors usually measure wall area, but many advertise prices per square foot of floor because it is easier for customers. This calculator accepts floor area and estimates the walls for you.
How do I lower the cost of interior painting?
Move furniture and do light prep yourself, keep the same colour so one coat may be enough, and skip ceilings if they are in good condition.
Sources for the default values
Defaults are typical figures from these sources; change any value to match your situation.