Most painting contractors lose money not because they can't paint — it's because they underbid. They eyeball a room, throw out a number, and hope it works out. Sometimes it does. Often it doesn't.
A proper estimate takes 10 extra minutes and can mean the difference between a job that pays you well and one that you're subsidizing with your own time. Here's the process, step by step.
Step 1 — Measure the Space
Start with a tape measure. You need three separate measurements for each room:
- Walls: Walk the perimeter of the room and multiply total linear feet by ceiling height. Subtract 20 sq ft for each standard door and 15 sq ft for each window.
- Ceiling: Length × width. Only count this if you're painting it — not every job includes the ceiling.
- Trim: Baseboards, crown molding, and door/window casings. Count linear feet and price trim separately from walls — it takes longer per square foot.
Write these down for every room before you leave the site. Don't trust your memory.
Step 2 — Calculate How Much Paint You Need
One gallon of paint covers roughly 350–400 sq ft per coat. Most interior walls need two coats, especially when changing colors or painting over drywall. If the surface is bare or you're doing a dramatic color change, factor in a primer coat as well.
The formula: (Total sq ft ÷ 375) × 2 coats × 1.10 waste = gallons needed
Round up to the nearest whole gallon. You'd rather have a little extra than need an emergency Home Depot run mid-job.
Step 3 — Price Your Materials
Paint is the biggest materials cost, but don't stop there. A complete materials list includes:
- Paint (walls, ceiling, trim — these may be different sheens)
- Primer (if needed)
- Rollers, covers, brushes
- Painter's tape and plastic sheeting
- Drop cloths
- Caulk and patching compound
- Sandpaper
Once you have your materials total, add a 15–20% markup. You're not just buying paint — you're sourcing it, hauling it, returning what's unused, and taking on any quality risk. That markup is earned.
Step 4 — Estimate Labor Hours
Experienced painters typically cover:
- Rolling walls: 150–200 sq ft per hour
- Cutting in (brush work along edges): 80–120 linear feet per hour
- Trim painting: 60–80 linear feet per hour
Add setup and cleanup time — for most residential jobs, budget 1–2 hours per day for moving furniture, masking, and cleanup. For multi-day jobs, don't forget travel time to and from the site each day.
If you're sending a crew, multiply the hours by the number of people. Price each person's time at their respective labor rate.
Step 5 — Apply Overhead and Profit Margin
This is the step most contractors skip, and it's why many contractors are effectively working for below minimum wage when all costs are accounted for.
Overhead covers the costs of running your business that don't show up in any single job: insurance, vehicle payments, tools and equipment, phone, accounting software, licensing. Tally your annual overhead costs and divide by your billable hours per year to get your overhead rate per hour — then add it to every job.
On top of overhead, add a profit margin of 15–25%. This isn't paying yourself — this is the return on running the business. It funds growth, covers slow periods, and rewards you for the risk of self-employment.
Step 6 — Format and Deliver the Estimate
A professional written estimate builds trust and sets clear expectations. It should include:
- Customer name, address, and date
- Detailed scope of work (which rooms, which surfaces, how many coats, paint brand/sheen)
- Materials list with quantities
- Total price (itemized or lump sum — your preference)
- Payment terms (e.g., 25% deposit, balance on completion)
- Estimate validity period (e.g., "valid for 30 days")
Email it to the customer within 24 hours of the site visit. Contractors who follow up fast win more jobs — it signals professionalism and reliability before you've swung a brush.
Use the free painting estimate calculator — add rooms, set your labor rate, and get a complete bid breakdown in under a minute.
Common Mistakes to Avoid
Even experienced painters make these errors on estimates:
- Forgetting primer: On new drywall or major color changes, primer is a separate cost — don't absorb it.
- Not specifying paint quality: If the customer supplies cheap paint and the finish looks bad, that's now your problem. Specify the brand and product in your estimate.
- Underestimating trim: Trim is slow, detailed work. It always takes longer than walls per square foot.
- No allowance for drying time: Between coats you have downtime. Factor this into multi-coat jobs, especially if you're paying someone to wait.
A good estimate takes the guesswork out of pricing. When you know your numbers cold, you quote with confidence — and customers can tell.