Interior painting: price by the square foot, or by the room?
Ask ten painters how they price interior work and you will get square footage, per room, per wall, by the day, and "I look at it and I know".
They are all right, because none of those methods is actually what determines the cost. Preparation is.
Why square footage lies
Two rooms, both 12 by 14, both eight-foot ceilings. Same square footage.
Room A is an empty rental with flat drywall, one colour over the same colour, and no furniture.
Room B is a lived-in family room with built-in shelving, two windows with trim, a fireplace surround, a dark red wall going to off-white, picture hooks, a dozen nail holes and a sofa that does not move.
Room B is easily three times the labour. A square-foot number treats them as identical, and whichever one you quoted at will be wrong for the other.
Square footage works when the variation is small — new construction, apartments, repaints of the same stock. It falls apart in occupied homes, which is most residential work.
Why per-room is also a trap
Per-room pricing is easier for customers to understand and easier for you to quote on the spot. The trap is that "room" is not a unit of anything. A powder room with wainscoting and a nine-foot ceiling can out-cost a bedroom.
Per-room works when you qualify it: standard ceiling height, walls only, up to a given number of openings, furniture moved by the customer. The qualifiers are what make the number real.
What you are actually pricing
Break any interior job into four buckets and the right method becomes obvious:
Protection and setup. Moving and covering furniture, floor protection, masking. Scales with how lived-in the space is, not its area.
Preparation. Filling, sanding, caulking, scraping, priming stains, dealing with wallpaper residue or a failed previous coat. This is the bucket that varies by a factor of ten and the one customers never see.
Coverage. Walls, ceilings, trim, doors. This one genuinely does scale with area and number of coats.
Reinstatement and cleanup. Putting the room back, final detail, removal.
Only one of the four follows square footage. That is why painters who quote purely on area lose money on old houses and overcharge on new ones.
A hybrid that holds up
Quote coverage by area, and preparation by condition:
| Line | Example |
|---|---|
| Walls — 1,240 sq ft, 2 coats | $1,180 |
| Ceilings — 420 sq ft, 1 coat | $340 |
| Trim, 3 doors, 2 windows | $460 |
| Preparation — moderate (fill, sand, caulk, spot prime) | $380 |
| Protection, setup and cleanup | $220 |
| Total | $2,580 |
Preparation gets its own line with a named level — light, moderate, heavy — defined in a sentence each. Now a customer who wants a cheaper number has something real to decide about, and you are not silently absorbing eight hours of filling.
Say what you are assuming about colour
Dark to light is two coats and often a primer. Deep accent colours may need three regardless of what the tin claims. Write it:
Pricing assumes a one-shade change in the same colour family, two coats. A change from the existing dark red to an off-white adds a primer coat, $X.
Walk the room out loud
The reason painters quote by feel is that writing the above takes real time, and the customer is standing right there waiting.
Pro Speak Artisan is built for that moment: you walk the rooms and describe what you see — "family room, twelve by fourteen, nine-foot ceiling, two windows, built in shelving, dark red to off-white so primer plus two, moderate prep, furniture stays" — and the structured estimate comes back in about three seconds, priced from your own rates. Before and after photos tag to the same job and stay in your records.
The method you choose matters far less than whether preparation has its own line. That one habit decides whether old houses are your best work or your worst.