How much does a gallon of paint cover?
On a typical interior wall: 350 square feet per gallon, per coat. On smooth, previously painted drywall you might get 400. On heavy texture you will be lucky to get 250. The label number is a best case, not a promise.
The standard numbers
| Product | Typical coverage |
|---|---|
| 1 quart of wall paint | ~100 sq ft |
| 1 gallon, smooth painted drywall | 375–400 sq ft |
| 1 gallon, typical drywall | 350 sq ft |
| 1 gallon, textured wall | 300–325 sq ft |
| 1 gallon, brick or stucco | 200–275 sq ft |
| 1 gallon, bare drywall first coat | 250–300 sq ft |
| 1 gallon of primer | 200–300 sq ft |
| 1 gallon of ceiling paint | 350–400 sq ft |
| 1 gallon of exterior paint on siding | 250–350 sq ft |
Why the label overstates coverage
Coverage is tested on a sealed, non-porous test panel under lab conditions, applied at exactly the recommended wet mil thickness. Your wall is not that panel. Four things eat into the number:
- Porosity. Bare or patched drywall absorbs the first coat. Expect 20–30% less coverage on that coat specifically.
- Texture. Orange-peel and knockdown finishes increase surface area. The rougher the wall, the more paint disappears into the profile.
- Application method. Rolling puts down a thinner, more consistent film than spraying. Sprayers lose 15–20% to overspray and overlap; brushes on trim absorb more.
- Color and sheen. Deep base colors need more pigment volume. High-gloss finishes are less forgiving of thin spots, so people apply them heavier.
Quick reference: room by room
Assuming 8 ft ceilings, two coats, one door, two windows and 350 sq ft per gallon:
| Room | Wall area | Gallons (2 coats) |
|---|---|---|
| 5 × 8 bathroom | ~162 sq ft | 1 |
| 10 × 12 bedroom | ~278 sq ft | 2 |
| 12 × 12 bedroom | ~333 sq ft | 2 |
| 12 × 14 living room | ~365 sq ft | 3 |
| 16 × 20 living room | ~481 sq ft | 3 |
| Open-plan 20 × 30 | ~749 sq ft | 5 |
Run your own numbers with the paint calculator — it takes doors, windows and coats into account.
Quarts, gallons or five-gallon buckets?
- Under 100 sq ft — a quart. Touch-ups, a single accent wall, a small powder room.
- 100–350 sq ft per coat — one gallon. Most single rooms.
- Above 1,200 sq ft total — price a five-gallon bucket. It is usually 20–30% cheaper per gallon and avoids batch differences across the job.
Batch differences are real: two gallons mixed at different times can be slightly different shades. On a large open area, always buy all the paint at once.
How to test coverage on your own wall
If you want a number you can trust, do a test patch on an inconspicuous area — behind a door, or inside a closet:
- Mark out exactly 10 sq ft with painter's tape.
- Apply one coat at the thickness you intend to use across the room.
- Note how much paint the patch used (weigh the can, or measure the level drop).
- Multiply: if 10 sq ft used 0.03 gallon, your real coverage is about 330 sq ft per gallon.
Frequently asked questions
Does one gallon cover a whole room?
For a small bathroom or a 10 × 10 ft bedroom at one coat, often yes. For a two-coat repaint of a normal bedroom, no — plan for two gallons.
How much does a gallon of paint cost?
$25–$70 for interior wall paint in 2026, with mid-tier brands around $40–$55. Ceiling paint and primer are usually cheaper.
Can I stretch paint with water?
A small amount of water (up to about 1/2 cup per gallon) is normal for latex and helps flow, but adding more than that breaks the binder and ruins durability. Never water down exterior paint.
Do I need two coats if I am painting the same color?
Yes, for anything touching a high-traffic wall. One coat over an existing similar color can look fine dry but will not cover evenly once light hits it at an angle.