Most painters who work for themselves fail not because they can't paint — but because they can't estimate. They underbid jobs, run out of money, and burn out. Learning to estimate properly is what separates a painter with a job from a painter with a business.
Measuring square footage
Wall area: Width × height of each wall, subtract doors (20 sq ft each) and windows (15 sq ft each)
Ceiling area: Length × width of the room
Trim: Measure linear feet of baseboard, door casings, crown molding, and window trim
Rule of thumb: A gallon of latex paint covers 350–400 sq ft per coat on a smooth surface
Calculating materials
Item
Coverage
Notes
Interior latex paint
350–400 sq ft/gallon
Reduce by 20% on textured surfaces
Exterior paint
250–350 sq ft/gallon
Rough siding may need more
Primer
300–400 sq ft/gallon
New drywall absorbs more — budget extra
Caulk (tube)
~35 linear feet
Varies with gap size
Estimating labor
Prep takes as long as — often longer than — the actual painting
A 12' × 15' room (one coat) takes an experienced painter roughly 2–3 hours setup to cleanup
Always add time for: protecting floors, moving items, cutting in, two coats, and cleanup
Track your time on every job — your estimates get more accurate with each project
The path from employee to contractor
Contractor's license: Most states require one for jobs over a certain dollar amount — check your state's licensing board
Business license: Register as an LLC (typically $50–$200) for liability protection
Insurance: General liability ($1M minimum) — about $100–$200/month for a solo operator
Estimating software: Quick Bid, Jobber, or a well-designed spreadsheet
Marketing: Google Business Profile (free), Nextdoor (free), and before/after photos on Instagram
💡The smart path: Get hired. Work for 2–3 years. Learn the trade AND how a painting business runs from the inside. Save money. Take your first clients on weekends. When your side income matches your salary — make the jump. That's how most successful painting contractors got there.
Watch — how to estimate an interior paint job
Fast & Easy Interior Paint Job Estimates — Accurate Guide for Beginners & Pros (2024)
A working professional walks through exactly how to estimate an interior job from scratch — measuring square footage, calculating materials, pricing labor, and arriving at a number that actually makes you money. Built specifically for beginners.