Painting Estimate Calculator
Whether you are a painting contractor quoting a job or a homeowner checking whether a quote is reasonable, this painting estimate calculator provides a cost breakdown built from first principles. Enter the room or surface dimensions, the number of coats, your paint cost per gallon, the labour rate, and your desired profit margin to generate an itemised estimate covering materials and labour. The calculator deducts window and door areas from the paintable square footage and accounts for paint coverage rate to determine how many gallons you need. Use the result as the basis for a written quote or to cross-check a contractor's bid.
Painting estimate formula
Paintable sq ft = (Perimeter x Height) - (Windows x 15) - (Doors x 20)
Total sq ft to coat = Paintable sq ft x Coats
Gallons = Total sq ft / 375 (coverage per gallon)
Materials = Gallons x Paint Cost per Gallon
Labour Hours = Total sq ft / sq ft per Hour
Labour = Hours x Labour Rate
Suggested Quote = (Materials + Labour) / (1 - Margin / 100)
Frequently asked questions
How do painting contractors calculate their price?
Painters typically price by the square foot of paintable surface. Interior walls and ceilings run $2-6 per sq ft including labour and materials. Exterior painting runs $1.50-4 per sq ft. An alternative method is to calculate labour hours based on sq ft per hour of production (a professional can coat 150-200 sq ft per hour), add material costs, then apply a margin.
How much paint is needed per room?
One gallon of paint typically covers 350-400 sq ft with one coat. Calculate paintable square footage as: (Perimeter x Wall Height) - (Windows x 15 sq ft) - (Doors x 20 sq ft). Plan for two coats for most colour changes, which doubles your paint needs. Add 10-15% waste for cutting in, drips, and touch-ups.
What is included in a professional painting quote?
A professional quote includes: surface preparation (sanding, patching, priming), paint and primer materials, labour for cutting in and rolling, masking and protection of floors and fixtures, a specified number of coats, and cleanup. Additional charges apply for high ceilings (scaffolding), exterior pressure washing, and significant repairs.
Should I charge for prep work separately?
Many painters bundle prep into their overall price, but itemising it on the estimate helps clients understand what they are paying for and prevents scope disputes. Prep can represent 30-50% of total labour time on older homes with peeling paint, patching needs, or staining issues.
How many square feet can a painter cover per hour?
A professional painter rolling flat walls can cover 150-200 sq ft per hour. Cutting in (brush work at edges) takes significantly longer - roughly 50-75 sq ft per hour. Detailed trim work (baseboards, window casings, crown moulding) may only achieve 20-40 sq ft per hour. Account for the mix of surface types in your estimate.
Sources
- U.S. Bureau of Labor Statistics: Painters occupational outlook.
- IRS: Self-employed individuals tax center.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.