In this article
- The scope decision, in numbers
- Where the paintable area comes from
- Room by room
- All at once, or room by room?
- What moves the figure for your house
- Frequently asked questions
- How much paint for a 1,500 square foot house interior?
- Should I paint the ceilings while I am at it?
- Is it cheaper to paint the whole house at once?
- How much of the work is trim?
- How long does a 1,500 square foot interior take?
- Does the estimate include primer?
- Can I use the same paint on walls and ceilings?
- What if my house is more open plan than this?
A 1,500 square foot house takes about 25.25 gallons to repaint inside in two coats. But that number means little until you have answered one question: are the ceilings and trim in scope, or just the walls?
Walls only is 17.75 gallons. Everything is 25.25. That is a difference of roughly 7.50 gallons and, far more importantly, a difference of days on site.
The scope decision, in numbers
| Scope | Gallons at two coats | Labour hours |
|---|---|---|
| Walls only | 17.75 | 58 |
| Walls and ceilings | 23.50 | 78 |
| Full interior with trim | 25.25 | 110 |
Look at the hours column rather than the gallons. Adding trim to a walls and ceilings job costs only 1.75 more gallons but a large block of extra time, because nearly all of it is edge work rather than open surface. Scope decisions on an interior are labour decisions, not material ones.
Where the paintable area comes from
Floor area is not paintable area. For this house the two numbers are 1,500 and 4,383, and the second is the one that buys paint.
| Surface | Quantity | How it is measured |
|---|---|---|
| Walls | 3,294 sq ft | Perimeter times height, less 20 sq ft per door and 15 per window |
| Ceilings | 1,089 sq ft | Floor area of the rooms whose ceilings are painted |
| Trim | 431 linear ft | Measured by length, not area |
| Doors | 13 | Counted. A door is a repeatable unit of work |
| Windows | 12 | Counted. Glazing bars drive the time, not glass area |
| Paintable total | 4,383 sq ft | Against 1,232 sq ft of floor |
Openings matter twice over. They come out of the wall area, which lowers the paint, and they add cutting in around every frame, which raises the labour. That is why the 13 doors and 12 windows are listed as counts rather than folded into a square footage.
Room by room
A 9 room layout totalling 1,232 square feet of room floor. The rest of the 1,500 is hallway width, closets, stairs and the walls themselves.
| Room | Size | Wall (sq ft) | Ceiling (sq ft) | Trim (lin ft) | Gallons | Hours |
|---|---|---|---|---|---|---|
| Living room | 16 by 14 ft | 455 | 224 | 60 | 3.62 | 17.5 |
| Dining room | 14 by 12 ft | 418 | 168 | 50 | 3.13 | 13.9 |
| Kitchen | 13 by 11 ft | 397 | not painted | 55 | 2.12 | 9.7 |
| Master bedroom | 15 by 13 ft | 434 | 195 | 48 | 3.35 | 15.6 |
| Bedroom x 2 | 13 by 11 ft | 764 | 286 | 88 | 5.60 | 25.3 |
| Bathroom x 2 | 9 by 7 ft | 472 | 126 | 60 | 3.19 | 13.8 |
| Hallway | 18 by 5 ft | 354 | 90 | 70 | 2.37 | 12.3 |
| Whole house | 3,294 | 1,089 | 431 | 23.50 | 110 |
The two bathrooms are worth noting. Together they are a small share of the floor area and a much larger share of the difficulty, because a bathroom is mostly edges and awkward access around fittings.
All at once, or room by room?
At this size both are viable and they cost differently.
Doing the whole interior in one run is more efficient. One set up, one protection pass, one lot of materials, and the crew stays in rhythm. The whole job is about 110 hours, roughly 6.9 days for two painters.
Doing it room by room over months spreads the cost but repeats the fixed part every time. If you are hiring out, each visit carries its own travel, set up and minimum charge, so four separate visits cost noticeably more than one job covering the same total area.
The middle path most families take is zones: bedrooms in one go, then living areas, then the hall and stairs last because they are the disruptive part. That keeps somewhere clean to retreat to at every stage.
What moves the figure for your house
Ceiling height first. These rooms assume standard heights from the room presets. Add a foot across the house and every wall gains area proportionally, worth a couple of gallons at this size, without the floor area changing at all.
Then the surface itself. Textured walls have more real area than their measured area, and anything bare or freshly filled absorbs the first coat rather than sitting on it. The coverage guide explains why the number on the tin assumes conditions you rarely have.
Then primer, which is extra product rather than one of your two coats. Read do I need primer before painting before adding it to the list, because priming a sound previously painted wall is usually wasted effort and money.
Your own dimensions go into the interior painting calculator, which uses the same figures as this page.
Frequently asked questions
How much paint for a 1,500 square foot house interior?
Around 25.25 gallons for everything in two coats, or 17.75 gallons for walls alone. The paintable surface is about 4,383 square feet across 9 rooms, considerably more than the 1,500 square feet of floor the house is sold as.
Should I paint the ceilings while I am at it?
If the walls are being done and the ceilings are more than a few years old, yes. Fresh walls make a tired ceiling obvious, and doing them later means protecting the new walls all over again. They take the same product as the walls here, so it adds no separate purchase, only 5.75 gallons and the hours in the table above.
Is it cheaper to paint the whole house at once?
Per room, almost always. One mobilisation, one set up and one continuous run beats several separate visits, each of which repeats the fixed costs that do not scale with the size of the job.
How much of the work is trim?
Only 1.75 gallons of the 25.25, but a disproportionate share of the time. There are 431 linear feet of it here plus 13 doors and 12 windows, and all of it is cut in by hand rather than rolled.
How long does a 1,500 square foot interior take?
About 110 labour hours for two coats throughout, roughly 6.9 days with two painters. Around 33 of those hours go on preparation before any finish paint is opened.
Does the estimate include primer?
No. The figure is finish paint only. Primer is additional and is needed on bare or repaired plaster, stains, and large colour changes, rather than as a routine first coat everywhere.
Can I use the same paint on walls and ceilings?
Usually yes, and this calculation assumes it, which is why they share a gallon figure. Some people prefer a dedicated flat ceiling paint for a better finish overhead, in which case split 23.50 gallons into 17.75 for walls and the balance for ceilings and buy them separately.
What if my house is more open plan than this?
You will need less. Wall area follows perimeter, so the same 1,500 square feet arranged as fewer, larger rooms has less wall to paint. The room table above is the place to adjust: strike out the rooms you do not have and add the ones you do.
