A 10 × 12 room needs about 2 gallons
Using these planning assumptions, the room has 301 sq ft of paintable wall area after standard openings. At 350 sq ft per gallon with a 10% waste allowance, the exact estimate is 1.89 gallons. We recommend buying 2 gallons — see the calculator result panel for the optimal container combination.
A realistic 10 × 12 project
A 10 × 12 office has a 44-foot perimeter and 352 gross wall sq ft. After the standard 51 sq ft opening deduction, 301 sq ft remains. Two coats and the allowance use 1.89 gallons, placing the project just below a two-gallon purchase.
What is distinctive about this size?
Home offices often have cable plates, shelving anchors, and a wall hidden by a desk. Mark repairs before moving equipment and photograph cable locations so the second coat does not cover the reference marks.
Only about 0.11 gallon remains from two gallons, so this is not a good case for borrowing paint for a closet. Reserve the remainder for missed edges and final touch-ups.
Calculation for this room
| Room perimeter | 44 ft |
|---|---|
| Gross wall area | 352 sq ft |
| Door and window deduction | 51 sq ft (one door + two windows) |
| Coats | 2 |
| Calculated paint | 1.89 gal |
Tips for a 10 × 12 room
For a small bedroom or home office:
- Remove or cover furniture before painting — aim for a clear 3-foot workspace around each wall.
- Paint the ceiling first if included, then work top-down on walls to catch drips.
- Cut in edges with a 2½-inch angle brush before rolling for clean lines at corners and trim.
- If this is a frequently used room, choose a washable paint finish (eggshell or satin) for easier cleaning.
Before buying paint
This result is a starting point, not a substitute for the product label. Textured walls, fresh drywall, unsealed patches, and dramatic color changes reduce effective coverage. Measure oversized doors and windows separately, and calculate trim or closets as separate surfaces.
- Use the actual coverage printed on your selected paint can.
- Keep the 10% allowance for touch-ups and application loss.
- Prime new drywall, repairs, stains, or glossy surfaces when required.
- Mix multiple cans together ("boxing") before painting to ensure consistent colour.
What changes this estimate?
A one-foot increase in wall height adds 44 sq ft per coat. Adding the ceiling contributes 120 sq ft per coat. Use the calculator above for unusual openings, different coat counts, or a lower coverage rate for textured or porous surfaces.
Related room sizes
Compare all common room-size paint estimates →
Estimates are for planning; product instructions and field measurements take priority.