Paint coverage by room size
Use this table for a fast planning check, then use the Paint Calculator for your exact room. These examples use the same published formula as the calculator.
Published and reviewed: August 30, 2026 · Method: BetterHomeHabits calculator model
For a typical rectangular room with 8-foot walls, two coats and standard openings, many common bedrooms require roughly 2–3 gallons of wall paint. Exact needs change with room perimeter, openings, coats and the coverage printed on the paint can.
Reference table
| Room size | Net wall area | Calculated paint | Whole gallons to buy |
|---|---|---|---|
| 10 × 10 ft | 269 sq ft | 1.69 gal | 2 gal |
| 10 × 12 ft | 301 sq ft | 1.89 gal | 2 gal |
| 12 × 12 ft | 333 sq ft | 2.09 gal | 3 gal |
| 12 × 15 ft | 381 sq ft | 2.39 gal | 3 gal |
| 15 × 20 ft | 509 sq ft | 3.20 gal | 4 gal |
| 20 × 20 ft | 589 sq ft | 3.70 gal | 4 gal |
Assumptions used
- 8 ft wall height
- 1 standard door (21 sq ft)
- 2 standard windows (15 sq ft each)
- 2 coats
- 350 sq ft coverage per gallon
- 10% waste allowance
Why your result may differ
Real projects can differ because of product coverage, layout, waste, openings, moisture, compaction, site condition, labor scope or measurement error. Treat the table as a benchmark and use the linked calculator with the specifications for your actual project.
Methodology
The table is generated from the same transparent calculation method used by BetterHomeHabits calculators. We publish the assumptions so the numbers can be reproduced and challenged.