Paint for a 13 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
| Paint | 2.81gal |
|---|---|
| What to buybuckets only pay from about 3.6 gal | 3 × 1 gal |
| Wall area450 ft² less 1 door and 1 window | 414ft² |
| Spread rateorange peel or knockdown adds surface area | 275ft²/gal |
| First coat | 1.51gal |
| Each later coat14.999999999999991% further — the surface is sealed now | 1.31gal |
| Doubling the first coat would say0.2 gal more than you need | 3.01gal |
| Masking tape81 ft of edge | 260 yd rolls |
- Room length
- 13 ft
- Room width
- 12 ft
- Ceiling height
- 9 ft
- Surface
- a textured wall
- Coats
- 2
- Doors
- 1
What to buy
2.81 gallons — 3 × 1 gal.
414 ft² of wall after openings, at 275 ft² per gallon on a textured wall.
Spread rate belongs to the surface, not the tin
The "400 square feet per gallon" printed on a can is measured on smooth primed drywall. a textured wall takes about 275, and that difference is the single biggest reason people run out.
Rough and porous surfaces are worst: stucco can halve the figure on the label.
The second coat is cheaper than the first
Once the surface is sealed, paint spreads about 15% further. 2 coats here comes to 2.81 gallons — not 3.01, which is what doubling the first coat would say.
That difference is 0.2 gallons of paint that would sit in the garage until it went off.
Box it before you start
Pour every tin into one bucket and mix. Tins of the same color from different batches differ slightly, and a wall painted from two tins shows the join exactly where you stopped for lunch.
Trim does not scale with the room
Doors, trim and ceilings are linear-foot work and a completely separate calculation. A room needing 2.81 gallons of wall paint typically takes under a quart of trim enamel.
Cutting in is the job
81 ft of edge here — that is where the hours go, not the rolling. A good 2½″ angled sash brush beats tape on most edges; tape earns its place mainly against carpet and glass.
Notes
- **Spread rate is a property of the surface, not the paint.** Textured wall takes about 275 ft² per gallon — orange peel or knockdown adds surface area. The "400 square feet" on the tin is measured on smooth primed drywall, which is the best case and rarely the case.
- **The second coat is cheaper than the first.** Once the surface is sealed, paint spreads about 14.999999999999991% further. 2 coats here is 2.81 gal, not 3.01 — doubling the first coat over-buys by 0.2 gal, which at retail is real money left in the garage.
- Buy all of it in one go and box it — pour every tin into one bucket and mix. Tins of the same colour from different batches differ slightly, and a wall painted from two tins shows the change where they met.
- Trim, doors and ceilings do not scale with floor area — they scale with linear feet, and they are a separate calculation. A room that takes 2.81 gal of wall paint typically takes under a quart for the trim.
- Cutting in is where the time goes, not rolling. 81 ft of edge here. A decent 2½″ angled sash brush and a steady hand beat tape on most edges, and tape is worth it mainly against carpet and glass.
Nearby sizes
- Paint for a 12 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 14 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 11 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 15 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 11 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 13 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 10 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 14 ft room with 9 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 12 ft room with 8 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 12 ft room with 10 ft ceilings on a textured wall, 2 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on new drywall, 2 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on wood siding, 2 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on primed drywall, 2 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on stucco, 2 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on a textured wall, 1 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on a textured wall, 3 coats
- Paint for a 13 × 12 ft room with 9 ft ceilings on a textured wall, 2 coats
Read more
- Paint Coverage per Gallon by Surface — the Full Table, and Why the Label Is OptimisticEvery label says 400 square feet. Almost no real surface delivers it, and the ones that miss badly miss by half.
- Cost to Paint a Room — Where the Money Goes, and Why Trim Costs More Than WallsPaint is about a tenth of the bill. Prep and trim are most of it, and trim does not scale with room size at all.
- How Much Paint for a Room — Spread Rate Belongs to the Surface, Not the TinChoosing paint by the coverage claim on the label compares products on a number that describes a wall you do not have.
- How Much Exterior Paint — Texture Decides It, Not BrandThe gap between smooth fibre cement and bare brick is nearly three to one. The gap between the cheapest and dearest paint is nothing like that.