Painting looks simple from the outside. Brush, roller, paint, wall. But pricing a painting job accurately is one of the harder estimating challenges in the trades because the variables are hidden. Two identical-looking rooms can take wildly different amounts of time depending on the condition of the walls, the number of coats needed, the amount of trim, and whether the homeowner picked a dark color to cover with white.
Underpricing painting work is epidemic. The trade has a low barrier to entry, which means there's always someone willing to do it cheaper. The painters who survive and build businesses are the ones who price based on real numbers, not gut feelings, and who send professional estimates that justify their rates.
Here's how to estimate painting jobs — interior, exterior, and commercial — with real rates and the adjustments that separate accurate estimates from money-losing guesses.
Interior Painting: The Core Math
Interior painting is priced per square foot of paintable surface — not floor area. A 12x14 room with 9-foot ceilings doesn't have 168 sq ft of painting (that's the floor). It has roughly 560-600 sq ft of paintable surface (walls + ceiling, minus windows and doors).
How to Measure
- Measure each wall: length x ceiling height
- Add all walls together for total wall area
- Subtract openings: ~20 sq ft per standard window, ~21 sq ft per door
- Add ceiling if included: room length x width
- Count trim separately: measure linear feet of baseboards, crown, casing, chair rail
Interior Rates (Ontario, 2026)
| Service | Rate | Notes |
|---|---|---|
| Walls — standard (2 coats, minimal prep) | $3.50-$4.50/sq ft | New construction or good condition |
| Walls — repaint (2 coats, moderate prep) | $4.00-$5.50/sq ft | Patching, sanding, priming spots |
| Walls — heavy prep (skim coat, dark-to-light) | $5.50-$7.00/sq ft | Multiple coats, extensive repair |
| Ceilings — flat | $2.50-$4.00/sq ft | Standard height, spray or roll |
| Ceilings — textured / cathedral | $4.00-$6.00/sq ft | Height premium, scaffold needed |
| Trim — baseboard, casing | $2.00-$3.50/lin ft | Sand, prime, two coats |
| Crown molding | $3.00-$5.00/lin ft | Height and detail premium |
| Doors (per door, both sides) | $80-$150 each | Includes prep and hardware masking |
| Cabinets (kitchen, per linear foot) | $40-$80/lin ft | Spray application, includes prime |
| Stairwell / high walls | $5.00-$8.00/sq ft | Scaffold setup, safety premium |
Example: Whole Interior Repaint
A typical 1,800 sq ft (floor area) bungalow with 9-foot ceilings, 12 rooms including hallways and closets:
| Line Item | Qty | Rate | Total |
|---|---|---|---|
| Walls — repaint, 2 coats (including prep) | 3,200 sq ft | $4.50 | $14,400 |
| Ceilings — flat, 2 coats | 1,800 sq ft | $3.00 | $5,400 |
| Baseboard trim | 480 lin ft | $2.50 | $1,200 |
| Door and window casing | 320 lin ft | $2.75 | $880 |
| Interior doors (both sides) | 14 | $110 | $1,540 |
| Paint supply (contractor grade premium) | 22 gal | $55 | $1,210 |
| Primer (for spots and new patches) | 4 gal | $45 | $180 |
| Supplies (tape, plastic, caulking, sandpaper) | 1 lot | $250 | $250 |
| Move/cover furniture (per room) | 12 | $35 | $420 |
| Subtotal | $25,480 | ||
| HST (13%) | $3,312 | ||
| Total | $28,792 |
That's a real job with real line items. A crew of 3 painters could complete this in 6-7 working days. Your labor cost (burdened, 3 painters x 7 days x 8 hrs x $40/hr avg) is roughly $6,720. Materials are $1,640. That leaves $17,120 gross profit on $25,480 — a 67% gross margin. Painting margins are high if you price correctly.
Exterior Painting: The Prep Problem
Exterior painting is more expensive per square foot than interior because of prep. Weather, sun exposure, and age mean exterior surfaces almost always need scraping, sanding, caulking, and priming before paint goes on. Prep is 50-70% of the labor on an exterior job.
Exterior Rates (Ontario, 2026)
| Surface | Rate (installed) | Notes |
|---|---|---|
| Vinyl/aluminum siding | $3.50-$5.00/sq ft | Clean, light sand, 2 coats |
| Wood siding — good condition | $4.50-$6.50/sq ft | Light scrape, prime spots, 2 coats |
| Wood siding — heavy prep | $6.50-$10.00/sq ft | Full scrape, sand, prime, 2 coats |
| Stucco / masonry | $3.00-$5.00/sq ft | Pressure wash, fill cracks, elastomeric |
| Soffits and fascia | $4.00-$6.00/lin ft | Height premium, ladder/scaffold |
| Trim and shutters | $3.00-$5.00/lin ft | Sand, prime, 2 coats |
| Deck / fence staining | $3.00-$5.00/sq ft | Clean, sand, 2 coats stain |
| Front door (high-quality finish) | $200-$400 each | Sand, prime, spray, 2-3 coats |
Always include a separate line item for prep. "Surface preparation including power washing, scraping, sanding, caulking, and spot priming — $X." When the homeowner sees that prep is 40% of the quote, they understand why exterior painting costs what it costs.
Commercial Painting: Different Rules
Commercial work is typically higher volume, lower rate per square foot, but faster production because commercial spaces are usually empty (no furniture to move) with large unbroken walls.
Commercial rates in Ontario run $2.00-$4.00/sq ft for standard office/retail repaints. The margin is thinner per square foot, but you make it up on volume — a 5,000 sq ft office at $2.50/sq ft is $12,500 and a 3-person crew can knock it out in 3-4 days.
Key differences for commercial estimates:
- After-hours work. Many commercial jobs need to happen evenings or weekends. Build in a 15-25% premium for off-hours labor.
- Low-VOC requirements. Occupied commercial spaces often require low-VOC or zero-VOC paint. These products cost 20-30% more than standard.
- Ceiling heights. Commercial spaces often have 12-16 ft ceilings. Factor scaffold or lift rental into every commercial bid — $150-$400/day depending on the lift type.
- Warranty expectations. Commercial clients expect 3-5 year workmanship warranties on interior and 5-7 on exterior. Factor the callback risk into your pricing.
The 5 Pricing Mistakes Painters Make
1. Underestimating prep. The number one margin killer. You walk through the house, see walls that look fine, and price for two coats. Then you start and find 47 nail pops, three patched holes that were never sanded, and a ceiling with water stains. Always inspect prep conditions during the walkthrough and price accordingly.
2. Letting the customer supply paint. They buy the cheapest option at the box store. It doesn't cover in two coats, you need three, and you're now working an extra day for free. Always supply the paint yourself. You get contractor pricing (25-40% below retail), you control the quality, and you mark it up for clean margin.
3. Not charging for color changes. "We're just doing white throughout" turns into "Actually, the accent wall in the bedroom is going to be navy." Navy over white needs 3-4 coats and a tinted primer. That's an extra $300-$500 per room. Include a note in your estimate: "Price based on X color selections. Additional colors beyond X are $Y per room."
4. Forgetting move-out costs. Moving furniture, covering floors, masking fixtures, and protecting surfaces takes time. In a furnished home, budget 30-45 minutes per room for setup and teardown. That's $35-$50 per room if you itemize it, or bake it into your per-square-foot rate.
5. Flat-rate quoting. "Interior paint job — $8,000." That tells the homeowner nothing. They have no way to evaluate whether it's fair. Itemize your estimate: prep, walls, ceilings, trim, doors, paint supply, move/cover. Transparency builds trust and justifies higher prices.
FAQ
How much should I charge per square foot for interior painting?
$3.50-$6.00 per square foot of wall area for two coats of premium paint including prep, depending on condition. New drywall is cheaper; dark-to-light color changes or damaged walls push toward the high end. Ceilings, trim, and doors are priced separately.
How do I calculate square footage for a painting estimate?
Wall length x ceiling height for each wall, added together. Subtract ~20 sq ft per window and ~21 sq ft per door. Add ceiling (length x width) if included. A standard 12x14 room with 9-foot ceilings has roughly 560-600 sq ft of paintable surface.
Should I include paint in my estimate or have the homeowner buy it?
Always supply it yourself. You get contractor pricing (25-40% below retail), you control quality, and the markup is pure margin. When homeowners buy cheap paint, it doesn't cover in two coats and costs you extra labor — far more than any paint savings.
How much does exterior painting cost per square foot?
$4.50-$8.00/sq ft for standard residential in Ontario. Heavy prep (scraping, sanding, full prime) pushes toward $10+/sq ft. Prep is 50-70% of the labor on exterior work — always call it out as a line item.
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