Paint Coverage: How Much a Gallon and a Quart Really Cover

Updated September 2026 · Home Project Resources

Want your number first? Open the free Paint Calculator, or read on for how it works.

One gallon of interior latex covers about 350 square feet in one coat on smooth, previously painted drywall. The honest paint coverage band that manufacturers publish is 250 to 400 sq ft per gallon per coat, and where your can lands inside that band depends almost entirely on what you are rolling it onto. A quart covers about 87 sq ft at that same 350 rate, and a five gallon pail covers about 1,750 sq ft.

Two coats is the default, not a luxury. So a room with 350 sq ft of wall does not need one gallon, it needs two coats over 350 sq ft, which is 700 sq ft of rolling and two gallons in the cart.

Updated September 2026

Skip the arithmetic. Punch your room dimensions, doors, and windows into our free paint calculator and it gives you gallons and quarts to buy, with the touch-up allowance already built in. You can change the coverage rate to match the number printed on the can you actually want.

What the number on the can actually means

The coverage figure on a paint label is a laboratory figure. It assumes a sealed, smooth, non-porous surface, a full wet film applied at the recommended thickness, and no waste in the tray, on the roller, or on the drop cloth.

Your wall is not a laboratory. Texture adds surface area you cannot see, fresh joint compound drinks the first coat, and a roller cover holds a surprising amount of paint that never reaches a wall. That is why the same can that claims 400 lands closer to 300 in a real bedroom.

There is a second thing hiding in that number: film build. Spreading a gallon thinner to make it cover more square feet does not save you paint. It just means the color is not fully hidden, so you roll a third coat and use more paint than if you had applied two proper ones.

Paint coverage by surface, per gallon per coat

This is the table to work from. It is the same set of ranges our calculator uses, and it is the fastest way to decide whether to trust 350 or drop your assumption.

Surface	Typical range per gallon	Why it lands there
Smooth drywall, already painted	350 to 400 sq ft	Sealed and slick, the roller gives everything up
New drywall, primed	300 to 350 sq ft	Primer seals it, but joint compound still pulls
New drywall, unprimed	200 to 300 sq ft	Raw paper and mud drink the first coat, prime instead
Light texture or orange peel	300 to 350 sq ft	More surface area than it looks
Knockdown or heavy texture	250 to 300 sq ft	Every ridge is extra square footage
Bare or stained wood	250 to 350 sq ft	Grain and end grain soak up the first coat
Concrete block or brick	100 to 200 sq ft	Open pores swallow paint, block filler first
Popcorn ceiling	200 to 250 sq ft	Heavy texture, and it should be sprayed not rolled

Read that table once and the pattern is obvious. Smooth and sealed goes far, rough and thirsty does not. Concrete block is the extreme case: a gallon can disappear into a basement wall in half the area you expected, which is exactly why block filler exists as its own product.

Quart, gallon, pail: what each one covers

Can sizes are where people over-buy and under-buy at the same time. They buy a gallon for a closet and two quarts for a bedroom, and both decisions cost money.

Container	Volume	Covers at 350 sq ft per gallon
Sample pot	about 8 oz	20 to 25 sq ft, one coat
Quart	0.25 gal	about 87 sq ft
Gallon	1 gal	about 350 sq ft
Two gallons	2 gal	about 700 sq ft
Five gallon pail	5 gal	about 1,750 sq ft

A quart is the right can for trim, a small accent wall, or a closet interior. It is the wrong can for anything you would call a room, because four quarts cost more than one gallon and give you four partly used containers to store.

The five gallon pail is worth it once your total need passes about four gallons of the same color. It also gives you one consistent batch, which matters more than people expect on long walls where a slight batch difference can show in raking light.

The openings you get to subtract

Gross wall area is perimeter times ceiling height. Net wall area is that number minus every hole in the wall. Doors and windows are real square footage you do not paint, and on a small room they change the can count.

Opening	Nominal size	Square feet you subtract
Standard interior door	3 x 7 ft	21 sq ft
Patio slider or double door	6 x 7 ft	42 sq ft
Standard window	3 x 5 ft	15 sq ft
Small bathroom window	2 x 3 ft	6 sq ft
Large picture window	5 x 6 ft	30 sq ft

One caution. Subtract openings, but do not also subtract for furniture, outlets, or a fireplace you plan to cut in around. Cutting in around obstacles uses paint at roughly the same rate as open wall, and it uses far more of your time.

How to run the math in four lines

Here is the whole calculation, and it works for any room.

Perimeter = 2 x (length + width).
Gross wall area = perimeter x ceiling height.
Net wall area = gross minus every door and window.
Paint needed = net area x number of coats, divided by your coverage rate.

Then round up to real can sizes and add a touch-up allowance of about 5 percent. That allowance is not padding. It is the quart you will be glad you have when a chair back scuffs the hallway in March.

Worked example: a 12 ft by 14 ft bedroom

Take a bedroom that measures 12 ft by 14 ft with 8 ft ceilings, one door, and two standard windows. Walls are smooth and already painted, so 350 is a fair rate.

Perimeter: 2 x (12 + 14) = 52 ft
Gross wall area: 52 x 8 = 416 sq ft
Openings: one door at 21 plus two windows at 15 each = 51 sq ft
Net wall area: 416 minus 51 = 365 sq ft
Two coats: 365 x 2 = 730 sq ft of rolling
Gallons: 730 divided by 350 = 2.09 gallons
Plus 5 percent touch-up: about 2.19 gallons
Buy: 2 gallons and 1 quart

Now change one thing. Say the walls carry a knockdown texture, so the rate drops to 275. The same 730 sq ft now needs 2.65 gallons, and with the touch-up allowance you are buying 3 gallons. Same room, same coats, one more gallon, purely because of texture.

The ceiling is a separate line. A 12 by 14 ceiling is 168 sq ft, and two coats is 336 sq ft, which is one gallon of ceiling paint. Ceiling paint and wall paint are different products, so never blend them into a single number.

Trim is smaller than it feels. A 4 in baseboard around a 52 ft perimeter is only about 17 sq ft of paintable surface. Add the door casings and the door itself and you are still comfortably inside one quart of enamel for a single bedroom.

Room size chart: gallons for two coats

These are the round-number versions at 8 ft ceilings, 350 sq ft per gallon, two coats, one door and two windows removed, with the touch-up allowance included.

Room size	Wall area at 8 ft	Less 1 door, 2 windows	Two coats, buy
8 x 10 ft	288 sq ft	237 sq ft	1 gal 2 qt
10 x 12 ft	352 sq ft	301 sq ft	1 gal 3 qt
12 x 12 ft	384 sq ft	333 sq ft	2 gal
12 x 14 ft	416 sq ft	365 sq ft	2 gal 1 qt
14 x 16 ft	480 sq ft	429 sq ft	2 gal 2 qt
16 x 20 ft	576 sq ft	525 sq ft	3 gal 1 qt
20 x 24 ft	704 sq ft	653 sq ft	4 gal

If your ceilings are 9 ft rather than 8, multiply the wall area by 1.125. At 10 ft, multiply by 1.25. That is a full extra gallon on a big room, and it is the single most common reason a paint order comes up short.

Rather run your own numbers? Open the free Paint Calculator.

Coats: two is normal, three happens

Coverage and hide are not the same thing. Coverage is how far a gallon spreads. Hide is whether you can still see what was underneath. A paint can spread beautifully and still need a third coat.

You are looking at three coats when:

You are going from a dark color to a light one, especially over red, deep blue, or true black.
You are painting a saturated color, since deep bases carry more colorant and less white pigment, and reds and yellows are the worst offenders.
The wall has patches, skim coat, or repairs that flash differently in sheen.
You are covering marker, crayon, water stains, or smoke, none of which are a coats problem at all. They are a stain-blocking primer problem.

The math punishes you fast here. A 400 sq ft per gallon paint that needs three coats uses more material than a 300 sq ft per gallon paint that hides in two. Buy for hide, not for the coverage claim on the front of the can.

Primer coverage is its own number

Primer is not paint and does not spread like paint. Most primers publish 200 to 300 sq ft per gallon, and on raw drywall or bare wood you should size it at the low end.

Prime when you are working on new drywall, bare wood, patched areas, glossy existing paint, or any stain that would bleed. Skip it when you are rolling a similar color over sound, clean, previously painted walls.

A tinted primer is the quiet trick for hard colors. Having the store tint your primer toward the finish color turns a likely three-coat job into primer plus two, which usually costs less paint overall and definitely costs less time.

Exterior coverage: assume less, always

Exterior paint coverage sits lower than interior almost across the board, because exterior surfaces are rough, absorbent, and rarely flat.

Exterior surface	Plan on, per gallon per coat
Smooth fiber cement or previously painted siding	300 to 350 sq ft
Wood lap siding, sound and painted	250 to 350 sq ft
Rough sawn or cedar shakes	150 to 250 sq ft
Stucco, light texture	150 to 250 sq ft
Stucco, heavy texture	100 to 175 sq ft
Brick or concrete block	100 to 200 sq ft

Shakes and heavy stucco are the classic budget-wreckers. All those edges and pockets multiply the true surface area, and the first coat is essentially feeding the substrate rather than covering it. Measure the wall, then cut your assumed rate rather than trusting the label.

Sprayer, roller, brush: application changes everything

The same paint, on the same wall, covers different amounts depending on how it gets there.

Roller. The baseline every published number assumes. A 3/8 in nap on smooth walls is efficient. A 3/4 in nap on texture holds more paint and puts more on the wall, so your rate drops.
Brush. The most efficient by volume, the slowest by far. Good for trim, useless for a whole room.
Airless sprayer. Fastest by a wide margin, and hungriest. Overspray, priming the hose, and the material left in the pump mean you should plan on 20 to 30 percent more paint for a sprayed job than a rolled one. On a popcorn ceiling it is still the right call.
Back-rolling. Spraying and immediately rolling the same area pushes paint into texture and pores. It uses roughly as much paint as spraying alone but gives you a far better bond on rough surfaces.

Buying rules that save a second trip

Round up to real can sizes, never down. Paint stores sell gallons and quarts, not 2.09 gallons.

Buy all of one color at once. Batch-to-batch variation is small but visible on a long wall in side light, and a store can box your gallons together to make them identical.

Keep the receipt and the color formula. A photo of the label on your phone has rescued more touch-up jobs than any amount of leftover paint in the garage.

Store leftovers properly. Wipe the rim, seal the lid with a rubber mallet rather than a hammer, and keep the can somewhere that never freezes. Latex that has frozen and thawed is done.

Where the estimate goes wrong

Most short orders trace back to one of five things:

Ceiling height. Nine and ten foot ceilings quietly add 12 to 25 percent to wall area.
Texture. Knockdown alone can take you from 375 to 275 sq ft per gallon.
Color change. A third coat is a 50 percent increase in material for the walls.
Counting only one coat. The label figure is per coat. It always was.
Forgetting closets, hallways, and the back of a door. They are small individually and add up to a quart.

Frequently asked questions

How much does a gallon of paint cover?

About 350 sq ft in one coat on smooth, previously painted drywall. The published band is 250 to 400 sq ft per gallon depending on the product and the surface. For two coats, one gallon covers roughly a 175 sq ft wall area.

How much wall does a quart of paint cover?

About 87 sq ft in one coat at the 350 rate, or roughly 43 sq ft at two coats. That is enough for a small accent panel, a closet interior, or the trim in one average room.

Do I really need two coats?

Almost always, yes. One coat leaves an uneven sheen and thin film that scuffs and washes badly, even when the color looks acceptable on day one. Fixing a sheen after the paint has cured is its own job, and how to make flat paint gloss covers the clear coat route. The only common exception is a light refresh in the exact same color over a sound, clean surface.

Does expensive paint cover more?

Sometimes it spreads slightly further, but the real difference is hide. Higher grade paints carry more solids and more pigment, so they usually reach full color in two coats where a cheaper paint needs three. Fewer coats means less material and much less labor.

How does primer change my paint order?

Primer replaces one finish coat on raw or patchy surfaces, and it seals the substrate so your finish coats spread at the top of their range instead of the bottom. Size primer at 200 to 300 sq ft per gallon and buy it as a separate line, not out of your paint total.

How much paint do I need for a 12x12 room?

At 8 ft ceilings with one door and two windows, a 12 by 12 room has about 333 sq ft of net wall. Two coats at 350 sq ft per gallon works out to two gallons, plus about a gallon of ceiling paint and a quart of trim enamel.

Should I buy a five gallon pail?

Once your need for a single color passes about four gallons, yes. You get one consistent batch and fewer containers to handle. Below that, individual gallons are easier to carry, stir, and store.

Why did my paint cover less than the can promised?

Texture, porosity, or spray application, in that order. Fresh drywall mud, bare wood, and knockdown texture all pull hard on the first coat, and an airless sprayer loses material to overspray and to the hose.