Planning result
A flat 12x12 ceiling is 144 square feet. With two coats, 10% waste, and 350 sq ft per gallon coverage, the estimate is about 0.91 gallons, so one gallon is a practical planning amount.
Assumptions
| Ceiling size | 12 ft by 12 ft flat ceiling. |
|---|---|
| Coats | Two coats for a refreshed finish. |
| Waste | 10% for roller loading, edges, and touch-ups. |
| Coverage | 350 sq ft per gallon per coat for ceiling paint. |
Calculation
| Step | Result | Formula |
|---|---|---|
| Ceiling area | 144 sq ft | 12 x 12 |
| Two-coat area | 288 sq ft | 144 x 2 |
| Waste-adjusted area | 317 sq ft | 288 x 1.10 |
| Estimated paint | 0.91 gallons | 317 / 350 |
| Practical buy | 1 gallon | Round up to full container size |
Texture changes the result
Popcorn, heavy texture, stains, and patched ceilings can use more paint than a smooth flat ceiling.
Keep ceiling paint separate
Ceiling paint is often flatter than wall paint. Estimate it as its own surface unless you are using the same product intentionally.
Next step
Use the linked calculator or planning hub to adjust dimensions, waste, coverage, depth, spacing, or product packaging for the real project.
Related guides
FAQ
Is one gallon enough for a 12x12 ceiling?
For this two-coat example, one gallon is the practical planning amount.
Does this include walls?
No. Walls should be estimated separately from the ceiling.
What if the ceiling is textured?
Use a lower coverage assumption or add more waste for heavy texture.