How much paint do I need for a 12×12 room?

Data checked October 2026

Short answer

A 12 × 12 ft room with 8-ft walls has 333 sq ft of wall to paint — 1.9 gallons for two coats, so buy 2 gal (about $115).

Wall area: 48 ft of perimeter × 8 ft = 384 sq ft, minus 1 door (21 sq ft) and 2 windows (15 sq ft each) = 333 sq ft.
Paint: 333 × 2 coats ÷ 350 sq ft/gal = 1.9 gal → 2 gal, the cheapest can mix at typical prices.
Ceiling too: 144 sq ft × 2 coats needs another 0.82 gal (1 gal).
Trim: 45 ft of 6-in baseboard plus door and window casing is 35 sq ft — 1 qt of semi-gloss covers two coats.
Brand calculators: Sherwin-Williams' says 1.8 gal (400 sq ft/gal); Benjamin Moore's says 2 gal (350 sq ft/gal).
Supplies (roller kit, covers, brush, tape, drop cloth) add about $75.16.

Adjust it to your exact job

Room size

Rooms

Same wall height and paint in every room.

Length

= 12' · 3.66 m

Width

= 12' · 3.66 m

Wall heightfloor to ceiling

= 8' · 2.44 m

Doors & windows

Doors

Windows

What are you painting?

Walls

Ceiling

Trim (baseboards & casings)

Trim area comes off the wall area so it isn't counted twice.

Situation & coats

What's on the walls now?

Two coats is the norm (Sherwin-Williams, Valspar Signature). Benjamin Moore and Valspar Reserve list 1 or 2 coats for a same-color refresh in a premium line.

Topcoats

Primer

Deep or bright color

Reds, yellows, navy: adds a coat unless you prime.

Paint

Wall paint

350 sq ft per gallon per coat — the low end of Sherwin-Williams' and Benjamin Moore's ranges, and the figure Benjamin Moore's calculator uses. Label: 2 coats.

Plan with coverage

sq ft/gal

Per coat. We plan at the low end of the label range so you don't run short.

Buy for the walls

2 gal

1.9 gal for 333 sq ft × 2 coats at 350 sq ft/gal · $115

Wall area to paint: 333sq ft384 sq ft minus 51 sq ft of openings
Ceiling: 144sq ftnot included
All paint & primer: 1.9galwalls
Paint + supplies: $190$115 paint · $75.16 supplies

What to buy for each surface
Surface	Area (sq ft)	Coats	Need	Buy	Cost
WallsTypical latex wall paint · 350 sq ft/gal	333	2	1.9 gal	2 gal	$115

Why brand calculators disagree

Sherwin-Williams' calculator (400 sq ft/gal, 21 sq ft per door, 15 per window) says 1.8 gal for 2 coats; Benjamin Moore's (350 sq ft/gal, always 2 coats, 12 sq ft per window) says 2 gal. We use your product's own label rate and your actual door and window sizes.

Shopping list

2 cans Typical latex wall paint — 1-gal can (walls)$115
1 packs 9 in roller covers, 3-pack, 3/8 in napa fresh cover for each product or color$6.43
1 kit Roller frame & tray kit$21.94
1 brush 2½ in angled sash brushfor cutting in$13.94
1 rolls Painter's tape, 1.88 in × 60 yd (ScotchBlue 2090)94 ft of baseboard and casing to mask$7.88
1 cloths Canvas drop cloth, 9 × 12 ftone per room, moved along the walls$24.97
1 set Lightweight spackle & sanding spongepatch nail holes and dents first

Estimated total$190

Cost estimate

Tap a price to use your store's

Typical latex wall paint, 1-gal can (walls)
2 cans × $typical price — no verified listing
$115
9 in roller covers, 3-pack, 3/8 in nap
1 packs × $
$6.43
Roller frame & tray kit
1 kit × $
$21.94
2½ in angled sash brush
1 brush × $
$13.94
Painter's tape, 1.88 in × 60 yd (ScotchBlue 2090)
1 rolls × $
$7.88
Canvas drop cloth, 9 × 12 ft
1 cloths × $
$24.97

Materials total$190

Online prices checked October 23, 2026 (Sherwin-Williams, Benjamin Moore, Walmart). Tap any price to enter your store's.

Did this answer your question?

Compare

Paint for a 12×12 room by plan (typical 350 sq ft/gal paint)

Plan	Gallons	Buy	Paint cost
Walls, 1 coat (same-color refresh)	0.95	1 gal walls	$57.59
Walls, 2 coats	1.9	2 gal walls	$115
Walls + ceiling, 2 coats	2.73	2 gal walls + 1 gal ceiling	$173
Walls + ceiling + trim	2.73	2 gal walls + 1 gal ceiling + 1 qt trim	$196
New drywall: primer + 2 coats	3.01	2 gal walls + 1 gal + 1 qt primer	$149
Deep color, no primer (3 coats)	2.85	3 gal walls	$173

How this was worked out

12×12 is the classic bedroom size and the most-asked paint question. Two gallons covers the walls twice with a little to spare.

The full method, material data and tips are on the main paint calculator page.

Similar jobs

Other sizes people check

Sources

Data behind this answer

Sherwin-Williams Paint Calculator (help text and AjaxPaintCalculator responses) — results are per coat at 400 (interior), 350 (exterior) and 250 (deck) sq ft/gal; 3×7 ft doors and 3×5 ft windows; trim area = LF × height subtracted from the wall; railings × 0.6, or × 2.0 with spindles; gables = width × peak ÷ 2 · checked October 2026
Benjamin Moore Paint Calculator (calculator code) — walls only, 350 sq ft/gal × 2 coats, 21 sq ft doors and 12 sq ft windows, gallons + quarts · checked October 2026
Sherwin-Williams Emerald Interior — PDS 101.08MAB — 350–400 sq ft/gal at 4 mils wet; drywall: self-prime with 2 coats or primer + 2 coats; drastic color change: prime · checked October 2026
Sherwin-Williams SuperPaint Interior — PDS 101.02A — 350–400 sq ft/gal; primer + 2 coats on new surfaces · checked October 2026
Sherwin-Williams Duration Home Interior — PDS — 350–400 sq ft/gal · checked October 2026
Benjamin Moore Regal Select — TDS N549 — 400–450 sq ft/gal; $84.99/gal online · checked October 2026
Benjamin Moore ben — TDS N626 — 400–450 sq ft/gal, self-priming · checked October 2026
Behr Ultra Scuff Defense Interior — product label (Home Depot-hosted PDF, rev. 09/20) — 250–400 sq ft/gal; tinted primer coat for drastic color changes · checked October 2026
Valspar Signature, Ultra & Reserve interior — product pages — Signature 200–400, Ultra 300–400, Reserve 400 sq ft/gal; fully loaded roller ≈ 9 sq ft · checked October 2026
Glidden Fundamentals & High Endurance Plus — Walmart.com listings — gallon, quart and 5-gal prices, Oct 23 2026 · checked October 2026
Clark+Kensington interior & exterior — Ace Hardware listings — interior 400–450, exterior 350–450 sq ft/gal; satin $42.99/gal, $20.99/qt, $219.99/5 gal (search snapshot Oct 2026) · checked October 2026
KILZ 2 All-Purpose Primer — Walmart.com listing — 300–400 sq ft/gal; $9.97 qt, $23.97 gal, $65 3.5 gal, $94 5 gal · checked October 2026
Zinsser Bulls Eye 1-2-3 — TDS (rev. 02/07/2025) — 400–450 sq ft/gal; practical 450 non-porous / 350 porous (assumes 15% loss) · checked October 2026
Sherwin-Williams Premium Wall & Wood Primer — PDS 108.38 — 400 sq ft/gal at 4 mils wet · checked October 2026
Sherwin-Williams online prices (homeowner product pages) — quart, gallon and 5-gal guest prices, Oct 23 2026; 5-gal pails ≈1% cheaper per gallon · checked October 2026
Painting supplies — Walmart.com listings — ScotchBlue 60 yd $7.88; 9×12 canvas drop cloth $24.97; 3-pack roller covers $6.43; tray kit $21.94; 2½ in sash brush $13.94 · checked October 2026
US EPA — Lead Renovation, Repair and Painting Program — about three-quarters of US homes built before 1978 still contain some lead-based paint · checked October 2026

Short answer

A 12 × 12 ft room with 8-ft walls has 333 sq ft of wall to paint — 1.9 gallons for two coats, so buy 2 gal (about $115).

Wall area: 48 ft of perimeter × 8 ft = 384 sq ft, minus 1 door (21 sq ft) and 2 windows (15 sq ft each) = 333 sq ft.

Paint: 333 × 2 coats ÷ 350 sq ft/gal = 1.9 gal → 2 gal, the cheapest can mix at typical prices.

Ceiling too: 144 sq ft × 2 coats needs another 0.82 gal (1 gal).

Trim: 45 ft of 6-in baseboard plus door and window casing is 35 sq ft — 1 qt of semi-gloss covers two coats.

Brand calculators: Sherwin-Williams' says 1.8 gal (400 sq ft/gal); Benjamin Moore's says 2 gal (350 sq ft/gal).

Supplies (roller kit, covers, brush, tape, drop cloth) add about $75.16.

Adjust it to your exact job

Room size

Rooms

Same wall height and paint in every room.

Length

= 12' · 3.66 m

Width

= 12' · 3.66 m

Wall heightfloor to ceiling

= 8' · 2.44 m

Doors & windows

Doors

Windows

What are you painting?

Walls

Ceiling

Trim (baseboards & casings)

Trim area comes off the wall area so it isn't counted twice.

Situation & coats

What's on the walls now?

Two coats is the norm (Sherwin-Williams, Valspar Signature). Benjamin Moore and Valspar Reserve list 1 or 2 coats for a same-color refresh in a premium line.

Topcoats

Primer

Deep or bright color

Reds, yellows, navy: adds a coat unless you prime.

Paint

Wall paint

350 sq ft per gallon per coat — the low end of Sherwin-Williams' and Benjamin Moore's ranges, and the figure Benjamin Moore's calculator uses. Label: 2 coats.

Plan with coverage

sq ft/gal

Per coat. We plan at the low end of the label range so you don't run short.

Buy for the walls

2 gal

1.9 gal for 333 sq ft × 2 coats at 350 sq ft/gal · $115

Wall area to paint: 333sq ft384 sq ft minus 51 sq ft of openings
Ceiling: 144sq ftnot included
All paint & primer: 1.9galwalls
Paint + supplies: $190$115 paint · $75.16 supplies

What to buy for each surface
Surface	Area (sq ft)	Coats	Need	Buy	Cost
WallsTypical latex wall paint · 350 sq ft/gal	333	2	1.9 gal	2 gal	$115

Why brand calculators disagree

Shopping list

2 cans Typical latex wall paint — 1-gal can (walls)$115
1 packs 9 in roller covers, 3-pack, 3/8 in napa fresh cover for each product or color$6.43
1 kit Roller frame & tray kit$21.94
1 brush 2½ in angled sash brushfor cutting in$13.94
1 rolls Painter's tape, 1.88 in × 60 yd (ScotchBlue 2090)94 ft of baseboard and casing to mask$7.88
1 cloths Canvas drop cloth, 9 × 12 ftone per room, moved along the walls$24.97
1 set Lightweight spackle & sanding spongepatch nail holes and dents first

Estimated total$190

Cost estimate

Tap a price to use your store's

Typical latex wall paint, 1-gal can (walls)
2 cans × $typical price — no verified listing
$115
9 in roller covers, 3-pack, 3/8 in nap
1 packs × $
$6.43
Roller frame & tray kit
1 kit × $
$21.94
2½ in angled sash brush
1 brush × $
$13.94
Painter's tape, 1.88 in × 60 yd (ScotchBlue 2090)
1 rolls × $
$7.88
Canvas drop cloth, 9 × 12 ft
1 cloths × $
$24.97

Materials total$190

Online prices checked October 23, 2026 (Sherwin-Williams, Benjamin Moore, Walmart). Tap any price to enter your store's.

Plan

Gallons

Buy

Paint cost

Walls, 1 coat (same-color refresh)

0.95

1 gal walls

$57.59

Walls, 2 coats

1.9

2 gal walls

$115

Walls + ceiling, 2 coats

2.73

2 gal walls + 1 gal ceiling

$173

Walls + ceiling + trim

2.73

2 gal walls + 1 gal ceiling + 1 qt trim

$196

New drywall: primer + 2 coats

3.01

2 gal walls + 1 gal + 1 qt primer

$149

Deep color, no primer (3 coats)

2.85

3 gal walls

$173