Paint by room size — gallons for two coats
Wall paint only, two coats at 350 sq ft per gallon, with three openings deducted at 20 sq ft each (the same default the calculator above uses). The figure in brackets is the exact gallons before rounding up to whole cans, so a room close to the next can is usually worth buying up. Ceiling paint is separate and is length × width. Two coats of flat stays under a gallon up to about 12 × 14. A tub or shower surround takes roughly another 60 sq ft off a bathroom, so the worked bathroom example below lands lower than this table.
| Room size | Wall area, 8 ft ceiling | 8 ft ceiling | 9 ft ceiling | 10 ft ceiling |
|---|---|---|---|---|
| 5 × 8 bathroom | 208 sq ft | 1 gal (0.85) | 1 gal (0.99) | 2 gal (1.14) |
| 8 × 10 | 288 sq ft | 2 gal (1.30) | 2 gal (1.51) | 2 gal (1.71) |
| 10 × 10 | 320 sq ft | 2 gal (1.49) | 2 gal (1.71) | 2 gal (1.94) |
| 10 × 12 | 352 sq ft | 2 gal (1.67) | 2 gal (1.92) | 3 gal (2.17) |
| 11 × 13 | 384 sq ft | 2 gal (1.85) | 3 gal (2.13) | 3 gal (2.40) |
| 12 × 12 | 384 sq ft | 2 gal (1.85) | 3 gal (2.13) | 3 gal (2.40) |
| 12 × 14 | 416 sq ft | 3 gal (2.03) | 3 gal (2.33) | 3 gal (2.63) |
| 12 × 16 | 448 sq ft | 3 gal (2.22) | 3 gal (2.54) | 3 gal (2.86) |
| 14 × 16 | 480 sq ft | 3 gal (2.40) | 3 gal (2.74) | 4 gal (3.09) |
| 15 × 20 | 560 sq ft | 3 gal (2.86) | 4 gal (3.26) | 4 gal (3.66) |
| 20 × 24 | 704 sq ft | 4 gal (3.68) | 5 gal (4.18) | 5 gal (4.69) |
Doors and trim — area, coats and paint to buy
Interior slabs at the standard 80 in height and 1 3/8 in thickness, both faces plus all four edges. Coverage at 350 sq ft per gallon, which makes a quart about 87 sq ft. Trim enamel is a different product from your wall paint and isn’t part of the can count above.
| Item | Area to paint | Coats | Paint to buy |
|---|---|---|---|
| Door slab, 24 × 80 in | 29 sq ft | 2 | 1 quart — 58 of 87 sq ft |
| Door slab, 28 × 80 in | 33 sq ft | 2 | 1 quart — 66 of 87 sq ft |
| Door slab, 30 × 80 in | 35 sq ft | 2 | 1 quart — 70 of 87 sq ft |
| Door slab, 32 × 80 in | 38 sq ft | 2 | 1 quart — 76 of 87 sq ft |
| Door slab, 36 × 80 in | 42 sq ft | 2 | 1 quart — 84 of 87 sq ft |
| Six-panel face, add 15% | 43 sq ft at 32 × 80 | 2 | 4 per gallon — 347 of 350 sq ft |
| Six-panel face, 36 × 80 | 48 sq ft | 2 | 3 per gallon |
| Jamb, 4 9/16 in deep | 6 sq ft per opening | 2 | — |
| Casing, 2 1/4 in, both sides | 6 sq ft per opening | 2 | — |
| Door, jamb and casing together | 50 sq ft | 2 | 1 gallon per 3 openings |
| Bifold closet, 4 ft, 4 panels | 59 sq ft | 2 | 1 gallon per 2 closets |
| Baseboard, 3 1/4 in | 31 sq ft per 100 linear ft | 2 | 1 quart per 140 linear ft |
| Window, 3 × 5 ft, cased | 9 sq ft | 2 | Add 6–8 sq ft for wood sashes |
| All the trim in a 12 × 12 room | 74 sq ft | 2 | 1 gallon — 148 of 350 sq ft |
How much paint do I need?
Work out the wall area, subtract the openings, multiply by coats and divide by the coverage rate on the can. For a smooth, previously painted wall that’s typically about 350 square feet per gallon.
What changes the coverage
Rough, porous or freshly patched surfaces drink paint, so drop to roughly 250–300 sq ft per gallon. Deep colors over light walls almost always need two coats plus a tinted primer, whatever the label promises.
How much paint to paint a door
A standard 32 × 80 in interior door takes one quart in two coats. Painted properly it’s about 38 square feet, made up of 17.78 a face on both faces plus 2.14 square feet of edge (224 inches of perimeter at the 1 3/8 in thickness every interior slab is built to).
A 30 × 80 door comes to 35 square feet and a 36 × 80 to 42. Two coats on the 32 is 76 square feet against the 87 a quart holds at 350 square feet per gallon, so every common interior size fits inside a quart. The 36 in is the tightest at 84.
Interior widths run 24, 28, 30, 32 and 36 inches. IRC R311.2 puts its 32 in clear width and 78 in clear height on the egress door alone, and says other doors aren’t required to comply. Check your local code or supplier before relying on that.
The frame breaks the quart. A 4 9/16 in jamb is about 6 square feet (198 inches of developed length around a 32 in opening at the jamb depth), and 2 1/4 in casing run on both sides of the wall adds roughly another 6. A complete opening is therefore around 50 square feet, and two coats on it is 100, past what a quart holds. Buy a quart for a slab on its own and a gallon for three complete openings.
Panel doors move the number again. The sticking and the panel bevels add somewhere around 15 to 20 percent, enough to turn four doors from comfortably inside a gallon to marginally over it. Nobody publishes that uplift, so buy on the flush figure and keep a quart in hand.
Use an enamel, not wall paint. Flat and eggshell wall paints stay soft and tear when the door is pulled open.
What decides it is blocking resistance, tested under ASTM D4946 (whether the dry film sticks to itself where a closed door presses against its stop in warm, humid weather). Waterborne alkyds are built for the job. Benjamin Moore rates Advance at 400 to 500 square feet per gallon with a 16 hour recoat and a 50 to 90°F application range, and Sherwin-Williams ProClassic is quoted at 350 to 400.
That 16 hour recoat is the real constraint rather than the paint volume. Two coats is a two-day job either way, so doors usually come off the hinges and go flat on sawhorses where the film can level. Brush the panels first, then the rails across, then the stiles top to bottom, so the last strokes run the full length of the door.
How much paint for a bedroom, bathroom, kitchen or living room
Budget two gallons for most bedrooms and three for a large one. A living room usually takes three to four, and a bathroom about one. At 8 ft ceilings with a door and a window deducted, a 10 × 12 bedroom needs 1.78 gallons, a 12 × 14 needs 2.15, a 14 × 16 primary bedroom 2.51 and a 16 × 20 living room 3.06. A 5 × 8 bathroom is 0.96. Those are the figures to check your own number against.
If you’re more than half a gallon off the room of the same size in the table below, the difference usually sits in the ceiling height or the opening count (more likely the ceiling height).
In a kitchen the wall figure is badly wrong, and it’s wrong in your favor. Cabinets cover 7 feet of an 8 foot wall on any run that has both base and wall units. That’s 36 inches to the top of the counter (a base cabinet box is 34.5 in and a counter 1.5), then the 18 in backsplash gap cabinets are normally hung to, then a 30 in wall cabinet.
Twenty linear feet of that in a 12 × 14 kitchen is about 140 square feet off a 416 square foot gross, which drops the buy from three gallons to two. Measure the cabinet runs and take them out the way you take out a door.
Bathrooms and bedrooms go opposite ways. A 60 in alcove tub with a surround to 6 ft covers about 60 square feet across three walls, so the finish coat in a 5 × 8 bathroom is nearer two thirds of a gallon than a full one. Buy the gallon anyway. Two coats over 216 square feet is two and a half quarts, and three quarts usually costs more than one gallon.
Bedrooms hide wall rather than covering it. Painting a closet the same color as the room keeps it inside the same cans, while painting it white makes it a separate purchase. Either way, a 6 × 2 ft reach-in closet has about 95 square feet of interior wall once the opening is deducted, and two coats of that is roughly half a gallon on its own.
Measure the walls, not the floor
Floor area is the wrong starting point, and it’s why so many people come home a gallon short. What you paint is the perimeter multiplied by the height, and two rooms with identical floor area can differ by about a quarter in wall area. A 12 x 12 room has a 48 ft perimeter and, at 8 ft, 384 square feet of wall. An 18 x 8 room covers the same 144 square feet of floor but has 416 square feet of wall, and a long 24 x 6 room has 480.
Run a tape around the perimeter, and measure the height rather than assuming eight feet. Ceilings of 9 and 10 ft add roughly 12 to 25 percent right away.
Ceilings and trim are separate jobs with separate products, and neither belongs in the wall figure. Ceiling area is simply length times width, and it’s usually painted in a dead flat so that roller laps and joint lines disappear.
Trim is easier to think about by the piece. A standard 36 x 80 in door is about 20 square feet a side, so a quart at the usual 350 square feet per gallon spread rate covers around 87 square feet (two coats on both faces of one door, with a little left for the edges). Baseboard, casing and window sashes come out of the same quart or two, not out of your wall gallons.
For anything that isn’t a rectangle, break it into shapes you can measure. A gable end or a sloped vaulted ceiling is a triangle (half the base times the height). A stairwell wall is a rectangle plus a triangle, measured from the lowest tread up to the ceiling. Bay windows, chimney chases and returns add wall you’ll forget if you work from a floor plan. And if you’re leaving one feature wall in a different color, split the measurement now, while you’re holding the tape, rather than trying to reconcile it at the paint counter.
Choosing a sheen, and what it costs you
Don’t trust the sheen name. Trust the gloss units. The Master Painters Institute grades finishes by their 60-degree gloss reading: G1 matte at a maximum of 5 units, G2 velvet at a maximum of 10, G3 eggshell at 10 to 25, G4 satin at 20 to 35, G5 semi-gloss at 35 to 70 and G6 gloss at 70 to 85.
One brand’s satin can measure lower than another brand’s eggshell, so a touch-up in the nominally same finish from a different product can flash badly. If you’re matching an existing wall, compare the gloss level on the data sheet rather than the word on the label.
The higher the sheen, the harder your preparation has to work. Matte scatters light and forgives sanding scratches, nail pops and taping ridges. Semi-gloss reflects, and every one of those defects shows under side lighting. Gloss and semi-gloss are the classic trigger for specifying a Level 5 skim coat on new board, which is the practical link between paint choice and drywall finishing.
Against that, sheen buys washability. Eggshell and satin belong in hallways, children’s rooms and kitchens, and semi-gloss belongs on trim, doors and bathroom walls that get wiped down.
Sheen changes technique as well as appearance. Anything above matte shows lap marks where a rolled edge dried before you got back to it, so work one wall at a time. Cut in a section and roll it out while the cut line is still wet, rather than cutting in the whole room first as many guides suggest. Stretching paint to make a gallon go further is probably the single most common cause of a patchy second coat, and of a third coat you never budgeted for. Keep the roller properly loaded and maintain a wet edge.
When 350 square feet per gallon doesn’t apply
The 350 figure comes straight off the data sheet. Sherwin-Williams specifies SuperPaint interior latex at 350 to 400 square feet per gallon applied at 4 mils wet, which is about 1.4 to 1.6 mils dry depending on the sheen. That number assumes a smooth, sealed, previously painted wall.
New drywall isn’t sealed. The board face paper and the joint compound drink at different rates, so it takes a PVA drywall primer first, and PVA typically covers 250 to 400 square feet per gallon depending on porosity. A skim-coated Level 5 wall sits at the top of that range. Untreated bare board and fresh compound sit at the bottom.
One note for Canadian readers. A 3.79 L can is exactly a US gallon, so every gallon figure here maps straight onto the can on the shelf. The 37 m² or 400 sq ft printed on a Canadian label is the manufacturer’s smooth-surface figure rather than the working one.
Masonry is a different order of magnitude. Bare concrete block can absorb a gallon per 100 square feet, which is why it gets sealed with a block filler rather than paint. Filler is quoted at roughly 75 to 125 square feet per gallon depending on whether the block is smooth or split face, and only after that does the finish coat reach about 200 to 250.
Textured plaster, knockdown and popcorn ceilings hide surface area that a tape measure can’t see. Assume 10 to 20 percent more paint than the flat equivalent, and more where the texture is deep and open.
Spraying breaks the arithmetic completely. Airless transfer efficiency is commonly quoted anywhere from 40 to 70 percent, meaning a real share of every gallon ends up as overspray rather than on the wall. You’re buying speed and a smoother film, not economy, so add material and mask properly.
Temperature matters too. Most interior latex data sheets set a minimum of 50°F (10°C) for air, surface and product alike, and the recoat time they print (four hours for SuperPaint) is measured at 77°F and 50 percent humidity, not in a cold room. That window stretches a long way as you drop toward the 50°F floor. Below it, cold paint doesn’t just dry slowly. It can fail to form a proper film at all.
How many gallons of paint for a 2000 sq ft house interior
Budget 23 to 26 gallons for two coats on the walls. Add 5 to 6 gallons for one coat on the ceilings and 2 to 4 for trim and doors, so call it 30 to 36 gallons all in, and up near 42 if every ceiling gets two coats.
The trap is wall area. A 2,000 square foot home has roughly 4,400 to 5,000 square feet of interior wall at 8 foot ceilings, not 2,000.
Interior wall runs about 2.2 to 2.5 times the floor area once you count both faces of every partition. It’s the same geometry drywall estimators use when they multiply floor space by 3.5 to get board area. That 3.5 is Fine Homebuilding’s published shortcut, and it covers ceilings too, which leaves 2.5 for walls alone.
Deduct roughly 10 percent for doors and windows, multiply by two coats, divide by 350 square feet per gallon, and a 2,000 square foot home lands near 24 gallons of wall paint. Published whole-house figures run lower, commonly 12 to 20, because those shortcuts quietly skip closets and assume a spread rate closer to 400. Buy five-gallon pails for anything over three gallons of one color (one tint batch, so no drift across a long wall).
How much paint for a 10x10 room with 2 coats
Two gallons. A 10 by 10 room has a 40 foot perimeter, so at an 8 foot ceiling that’s 320 square feet of wall, or 280 once you take off a door and a window at the flat 20 square feet per opening this calculator uses. Two coats is 560 square feet, or 1.6 gallons at 350 per gallon. Round up and buy two.
Don’t try to shave it with quarts. A gallon plus two quarts is 1.5 gallons, or 525 square feet, short of the 560 that two coats need. You’d end up buying three quarts on top, which usually costs more than a second gallon.
Ceiling height moves the answer. At 9 feet the room still fits inside two gallons at 1.83, but at 10 feet you cross 2.06 and need a third can.
The 100 square foot ceiling takes well under a gallon of flat for two coats. Box both gallons together in one bucket before you start so the cans can’t flash different on the last wall.
Do you subtract windows and doors when calculating paint
Yes, but only the big ones. Deduct about 20 square feet for a standard 36 by 80 inch door and roughly 15 for a typical 3 by 5 foot window. Leave anything smaller in the total. Cutting in around a small opening burns more paint per square foot than open wall does.
Does 20 square feet really matter when paint comes in whole cans? Only when the deduction crosses a rounding line, and it often does.
Three openings in a 12 by 12 room take 60 square feet off 384, and that’s the difference between buying three cans for two coats and buying two. The hit is hardest in glass-heavy rooms and whole-house counts. A 6 foot patio slider is 40 square feet on its own, and a wall of windows can swallow a third of the surface.
This calculator deducts a flat 20 square feet per opening, which is generous on windows, so if yours are small you can skip the deduction and accept the slight over-buy.
How much primer do I need per gallon of paint
Primer isn’t sized off paint volume. It’s one coat over the same area, and it just covers less. KILZ PVA drywall primer is rated 300 to 400 square feet per gallon and Zinsser Bulls Eye 1-2-3 at 350 on porous surfaces, against 350 for finish paint. Budget one gallon of primer per two gallons of paint.
That ratio comes straight from the coverage rates. One primer coat plus two finish coats over 350 square feet of bare board is one gallon of primer and two of paint. The calculator sizes primer at 300 square feet per gallon, which is the honest number for board paper and fresh joint compound (they drink at different rates). Zinsser’s own technical data sheet splits it: 450 square feet per gallon on non-porous surfaces, 350 on porous.
Have the primer tinted toward your topcoat when you’re going dark. Zinsser states plainly that doing so can eliminate a coat of finish paint, which is a bigger saving than any primer you skip.
Common questions
How much does a gallon of paint cover?
About 350 sq ft on smooth, sealed walls. On porous or textured ones it drops to roughly 250–300, depending on how much the surface drinks.
Do I need primer?
On bare drywall, patches, stains or a big color change, yes. Over sound paint of a similar color, a good self-priming paint is usually enough.
Should I deduct doors and windows?
Deduct roughly 20 sq ft per door or window. If you’d rather not bother, skipping the deduction is a safe way to over-buy slightly.
How much paint do I need for a 12x12 room?
With an 8 ft ceiling that’s 384 square feet of wall. Deduct three doors and windows at 20 square feet each and you have 324. Two coats is 648 square feet, or 1.85 gallons at 350 square feet per gallon, so buy two. The 144 square foot ceiling needs roughly another gallon for two coats of flat.
Will one gallon of paint cover a whole room?
Only in one coat, and only a small room. A gallon covers about 350 square feet in a single coat, which is roughly the four walls of a 10 x 10 room at 8 ft (320 square feet). Two coats therefore needs two gallons. Anyone promising a room per gallon is quoting one coat on a small, smooth, already-painted room with the same color underneath.
Is it cheaper to buy paint in 5-gallon buckets?
Per gallon it’s cheaper, yes, and you also get one continuous tint batch, which removes any color drift between cans on a long wall. It’s only cheaper if you use it, though. Interior paint runs roughly $20 to $60 a gallon (US, 2026) for standard and professional grades, with premium lines well north of $85, so a part-used tinted pail is real money sitting on a shelf.
What is the coldest temperature I can paint at?
Most interior latex data sheets specify a 50°F (10°C) minimum for air, surface and product. Below that the film doesn’t coalesce properly and you get poor adhesion and a chalky finish. Remember too that the recoat time on the label (four hours for SuperPaint) is measured at 77°F and 50 percent humidity, and it lengthens sharply as the room cools toward that 50°F floor.
How much does it cost to paint a room yourself?
For a 12 x 12 room, two gallons of wall paint at $20 to $60 each, a gallon of ceiling paint and a gallon of PVA primer if the board is new puts materials at roughly $100 to $250 (US prices, 2026). Add $40 to $80 for rollers, brushes, tape, a drop cloth and spackling compound if you’re starting with nothing.
How many gallons of paint for a 1,500 sq ft house interior?
Walls run roughly 3,300 to 3,750 square feet at 8 foot ceilings, so after a 10 percent deduction for openings, two coats at 350 square feet per gallon is 17 to 19 gallons. Add 4 to 5 for one coat on the ceilings and 2 to 3 for trim, so 23 to 27 gallons in total. Published whole-house figures run nearer 10 to 15 because they assume a 400 square foot spread rate and skip closets.
How much primer do I need for a 12 x 12 room of bare drywall?
Figure on about a gallon. The walls are 384 square feet gross, 324 after deducting three doors and windows, and primer covers around 300 square feet per gallon on new board, so 1.08 gallons. Buy a gallon plus a quart if the joint compound is fresh and the board is thirsty, or a second gallon if the ceiling is being primed too.
Is self-priming paint the same as using a separate primer?
Self-priming paint is a thicker topcoat. It seals sound, previously painted walls in a similar color, and it’s genuinely good at that job. On bare drywall, patches or stains it isn’t a substitute. Over new board, fresh compound, water stains or a big color change, a dedicated primer still goes on first and you still count two finish coats on top of it.
How much paint to paint a door?
Any standard interior door takes one quart in two coats. A 32 × 80 in slab is 17.78 square feet a face, and both faces plus 2.14 square feet of edge (1 3/8 in thick) come to about 38 square feet. Two coats is 76 against the 87 a quart holds at 350 square feet per gallon. A 30 × 80 door is 35 square feet and a 36 × 80 is 42, so both fit, the 36 with 3 square feet to spare.
How many doors will a gallon of paint cover?
A gallon does four flush doors in two coats, both faces and every edge (350 square feet against 76 per 32 × 80 door). Four six-panel doors of the same width fit too, but they use 347 of the 350 where four flush doors use 302. Three if the doors are 36 × 80 six-panels at 97 square feet each, and three if you’re painting the jamb and casing with every door, since a complete opening is 50 square feet rather than 38.
Will a quart of paint cover a door?
A quart covers one door in two coats, both faces and all four edges, with about 12 square feet spare on a 32 × 80. It won’t cover the door and its frame. Add a 4 9/16 in jamb at 6 square feet and 2 1/4 in casing on both sides at 6 more, and two coats on the whole opening is 100 square feet against the 87 in a quart. Two doors, or one door and its frame, means a gallon.
What kind of paint should I use for interior doors?
A satin or semi-gloss enamel, not wall paint. What matters is blocking resistance, the ASTM D4946 test (whether the dry film sticks to itself against the door stop). Flat and eggshell wall paints stay soft and tear when the door is opened. Waterborne alkyds are made for it. Benjamin Moore rates Advance at 400 to 500 square feet per gallon, a 16 hour recoat and a 50 to 90°F application range, and Sherwin-Williams ProClassic is quoted at 350 to 400.
Do panel doors need more paint than flush doors?
Panel doors take roughly 15 to 20 percent more. Sticking and panel bevels add surface the outside dimensions don’t show, so a 32 × 80 six-panel runs nearer 43 to 46 square feet against 38 flush. No manufacturer publishes a firm figure for that uplift. If flush doors put you near the top of a can, panel doors will push you past it. A molded hollow-core door with a shallow pressed profile sits close to the flush figure.
How much paint do I need for a door frame and casing?
Figure about 12 square feet per opening, or 24 square feet in two coats. A 4 9/16 in jamb around a 32 in door is 6 square feet (198 inches of developed length at the jamb depth), and 2 1/4 in casing run on both sides of the wall is 6 more. A quart covers the frames and casings on three openings. It won’t cover one opening plus its door, which is 100 square feet in two coats.
How much paint do I need for a bathroom?
Budget a gallon, and you’ll have some left. A 5 × 8 bathroom at 8 ft is 208 square feet of wall, 168 after a door and a window, so two coats is 336 against a gallon’s 350. A 60 in alcove tub with a surround to 6 ft takes another 60 square feet off across three walls, so the real need is about two thirds of a gallon. Still, 216 square feet is two and a half quarts, and three quarts costs more than a gallon.
How much paint do I need for a bedroom?
Most bedrooms take two gallons for two coats. A 10 × 12 bedroom at an 8 ft ceiling is 1.78 gallons once a door and a window come out, and a 14 × 16 primary bedroom at 2.51 needs three. Add half a gallon for every reach-in closet you paint inside. A 6 × 2 ft closet has about 95 square feet of interior wall once the opening is deducted, and two coats of that is 190 square feet.
How much paint do I need for a kitchen?
A 12 × 14 kitchen usually takes two gallons, not the three the raw wall area suggests. Cabinets cover 7 feet of an 8 foot wall wherever base and wall units run together (36 inches to the top of the counter, an 18 in backsplash gap, then a 30 in wall cabinet). Twenty linear feet of that is 140 square feet off a 416 square foot gross, and a door and a window take another 40, leaving 236 square feet and 1.35 gallons for two coats.
How much paint do I need for a living room?
Usually three to four gallons for two coats. A 12 × 18 living room at 8 ft works out at 2.51 gallons and a 16 × 20 at 3.06, and the same 16 × 20 at a 10 ft ceiling climbs to 3.89. The deduction most often missed in a living room is the cased opening to a hall or dining room. A 6 ft wide opening at 6 ft 8 in is 40 square feet, worth two standard openings on its own.