If you already know how many square feet of wall you are painting, the rest is a lookup. This guide is that lookup: one table, four label coverages, 100 to 1,000 square feet of wall, and then the part a table hides, which is where the purchase steps.
The steps matter more than people expect. At a 350 label the order climbs a quart about every 40 square feet of wall, so a wall of 397 square feet and a wall of 398 are a quart apart. If your number lands near a riser, two walls that feel identical go home with different cans.
One thing has to be true before the table means anything: the square feet you bring to it are wall, after doors and windows come off. If the number in your head came off a listing or a floor plan, it is floor area, and floor area is a different number — a 400-square-foot floor can sit under anywhere from 640 to 1,360 square feet of wall. That is a whole guide of its own: your floor area is not your wall area.
The table
Two coats, a 10 percent allowance, cans bought in gallons and quarts. Each column is the coverage printed on the can you are buying. The last column is the one exception: a single coat at a 350 label, for a repaint in the same color.
| Wall sq ft | 250 label | 350 label | 400 label | 450 label | One coat @ 350 |
|---|---|---|---|---|---|
| 100 | 1 gal | 3 qt | 3 qt | 2 qt | 2 qt |
| 150 | 1 gal + 2 qt | 1 gal | 1 gal | 3 qt | 2 qt |
| 200 | 2 gal | 1 gal + 2 qt | 1 gal + 1 qt | 1 gal | 3 qt |
| 250 | 2 gal + 1 qt | 1 gal + 3 qt | 1 gal + 2 qt | 1 gal + 1 qt | 1 gal |
| 300 | 2 gal + 3 qt | 2 gal | 1 gal + 3 qt | 1 gal + 2 qt | 1 gal |
| 350 | 3 gal + 1 qt | 2 gal + 1 qt | 2 gal | 1 gal + 3 qt | 1 gal + 1 qt |
| 400 | 3 gal + 3 qt | 2 gal + 3 qt | 2 gal + 1 qt | 2 gal | 1 gal + 2 qt |
| 450 | 4 gal | 3 gal | 2 gal + 2 qt | 2 gal + 1 qt | 1 gal + 2 qt |
| 500 | 4 gal + 2 qt | 3 gal + 1 qt | 2 gal + 3 qt | 2 gal + 2 qt | 1 gal + 3 qt |
| 600 | 5 gal + 2 qt | 4 gal | 3 gal + 2 qt | 3 gal | 2 gal |
| 700 | 6 gal + 1 qt | 4 gal + 2 qt | 4 gal | 3 gal + 2 qt | 2 gal + 1 qt |
| 800 | 7 gal + 1 qt | 5 gal + 1 qt | 4 gal + 2 qt | 4 gal | 2 gal + 3 qt |
| 900 | 8 gal | 5 gal + 3 qt | 5 gal | 4 gal + 2 qt | 3 gal |
| 1000 | 9 gal | 6 gal + 2 qt | 5 gal + 2 qt | 5 gal | 3 gal + 1 qt |
Read one row across and the table makes its own argument. Four hundred square feet of wall is 3 gallons and 3 quarts at a 250 label and 2 gallons flat at 450 — the same wall, nearly two gallons apart, decided by which can you pick up. Reading a column down is the other half: at a 350 label, every 40 square feet of wall is another quart, all the way up.
Which column is yours
The column headings are not grades of paint. They are the coverage figure printed on the can, and it is printed because manufacturers do not agree on one number.
Sherwin-Williams' calculator page says a gallon "typically covers about 350-400 square feet". Glidden says a gallon "typically covers up to 400 sq. ft. on primed, smooth, non-porous surfaces" — note up to, and note the three conditions. Behr prints "250-400 Sq. Ft. Coverage per Gallon" on a premium interior line. Benjamin Moore's data sheet for one product gives 400 to 450 square feet per gallon and adds that it depends on surface texture and porosity.
So the honest instruction is the dull one: use the number on the can in your hand, and if the can prints a range, start from the low end. A 250 column exists in the table because a real can prints 250 at the bottom of its range, and a porous or freshly patched wall is exactly the wall that lands there.
The 450 column is the opposite case. It is higher than the bottom of any range quoted above, so treat it as a best case rather than a plan.
Where it steps
A table of round numbers hides the thing that actually decides your trip to the shop. The purchase does not rise smoothly with your wall; it sits flat and then jumps a quart. At a 350 label in two coats, the jumps land here:
40 · 80 · 120 · 160 · 199 · 239 · 279 · 319 · 358 · 398 · 438 · 478 · 518 · 557 · 597
Those are the first square-foot values at which the order changes. A wall of 358 square feet buys 2 gallons and 2 quarts, and so does a wall of 397. At 398 it becomes 2 gallons and 3 quarts, and it stays there until 438.
That is the part worth carrying away. The difference between 397 and 398 square feet of wall is one square foot — a square the size of a floor tile — and it is a whole quart at the counter. If the number you measured sits within a few square feet of a riser, the sensible move is to run it twice: your measurement, and your measurement plus the bit you are not sure about.
Why a step is about 40 square feet
The step size is the wall that one quart does, and that is a short division. A quart is a quarter of a gallon, the gallon has to cover two coats, and the 10 percent allowance eats into it:
step = label ÷ coats ÷ 1.10 ÷ 4
At a 350 label that is 350 ÷ 2 ÷ 1.10 ÷ 4 = 39.8 square feet. One quart of paint, spread over two coats with the allowance kept, covers a patch of wall a bit under 40 square feet — roughly a 5-by-8-foot panel.
The same division gives the step for the other columns, and it is why the columns do not step together:
| Coverage on the can | One quart moves | One gallon moves |
|---|---|---|
| 250 sq ft/gal | 28.4 sq ft of wall | 113.6 sq ft |
| 350 sq ft/gal | 39.8 sq ft of wall | 159.1 sq ft |
| 400 sq ft/gal | 45.5 sq ft of wall | 181.8 sq ft |
| 450 sq ft/gal | 51.1 sq ft of wall | 204.5 sq ft |
The right-hand column is the one that surprises people, and it has its own guide: a can that says 350 does not cover 350 square feet of your wall, because the label is describing one coat on a prepared surface and your wall is getting two coats and a margin.
You will also notice the risers are not perfectly 40 apart — 160, then 199, then 239. The step is 39.8 square feet rather than 40, so the ladder drifts by a square foot every few rungs. The ladder is the exact thing; the round number is the approximation.
"A quart covers 100 square feet"
That figure is on the same Sherwin-Williams page as the gallon figure, and it is right on its own terms: a quart is a quarter of a 400-square-foot gallon, and a quarter of 400 is 100.
It is not the step in the table, and the gap is the whole point of this guide. The 100 is one coat, with no allowance. Put two coats and the 10 percent on it and the same quart is doing 45.5 square feet at a 400 label. Plan with 100 square feet to the quart on a two-coat job and you will buy a little under half of what you need.
That is not a mistake in the published figure. It is the difference between what a quart covers once and what a quart gets you through — and the table is built on the second one, because the second one is what you carry to the till. Whether your shop will sell you that quart at all is a separate question, and some lines are gallons only below a certain size.
If the shop only sells gallons
Plenty of products come in gallons and nothing smaller, and then the table collapses. Rounding up to whole gallons at a 350 label, two coats:
| Wall sq ft | Gallons and quarts | Gallons only |
|---|---|---|
| 100 | 3 qt | 1 gal |
| 200 | 1 gal + 2 qt | 2 gal |
| 300 | 2 gal | 2 gal |
| 400 | 2 gal + 3 qt | 3 gal |
| 500 | 3 gal + 1 qt | 4 gal |
| 700 | 4 gal + 2 qt | 5 gal |
| 1000 | 6 gal + 2 qt | 7 gal |
Two things follow. The rows where both columns agree — 300 here — are the rows where the quart was never going to help you, and chasing a more precise wall measurement on those rows changes nothing you buy. And on the rows where they differ, the step is four times as wide: in gallons only, the purchase holds steady for about 159 square feet of wall at a time instead of 40. A gallon-only product is far more forgiving of a rough measurement, right up to the moment it is not.
What the allowance is doing
Every figure above has 10 percent added before the rounding. That is not paint on the wall; it is the cut-in you redo, the roller you load the first time, the bit left in the tray, and the touch-up in six months.
It is also why the table never produces a bare-minimum answer. At 400 square feet of wall and a 350 label, the arithmetic needs 2.514 gallons and the table says 2 gallons and 3 quarts, which is 2.75 — about a quart of headroom from the rounding alone; the 10 percent allowance is already inside the 2.514. If you want to see the bare arithmetic, the calculator prints the unrounded gallons alongside the cans.
Drop the allowance to zero and every riser moves. Raise it to 15 percent for a textured wall and they move the other way. The allowance is a dial, not a constant, and the one in this table is the default.
Checking it on the calculator
The paint calculator does this in total-area mode: type the wall square feet you measured, set the coverage from your can, set the coats, and leave the allowance where it is unless you have a reason.
If you have room dimensions rather than a wall figure, use room mode instead and let it add the four walls — and then the openings field matters, because the table's "wall sq ft" is net. The default in that field is 20 square feet, about one door. What belongs in the openings box is worth reading if your room has a sliding door or a picture window, because a large opening is the one that moves a purchase.
Under every result the same line prints: "Ceiling, primer and trim are not included unless measured separately." The ceiling is a different surface with a different label on a different can.
What this table does not tell you
It does not tell you what your wall will actually drink. Coverage is published as a range because texture and porosity move it, and a wall that has just been skimmed or is changing color sits at the low end of whatever range your can prints. The range guide runs one room at both ends of a single label, and the purchase changes by whole gallons.
It does not tell you about cost. This site does not handle prices.
And it does not decide your coat count. Two coats is the table's assumption because that is what a color change needs; a repaint in the same color can be one, which is what the "1 or 2 coats" in that manufacturer's data sheet is describing. The last column of the table is there for that case. If you are weighing it across more than one room, two rooms and the coat question runs it both ways.
The count in one line
gallons to buy = ceil(wall sq ft × coats ÷ label × 1.10 × 4) ÷ 4 — the ceil rounds up to whole quarts; read 2.75 as 2 gallons and 3 quarts.
Find your wall square feet in the left column, read across to your can's coverage, and check whether you are sitting within a few square feet of a riser. If you are, measure again before you buy.
Sources
Every product figure was read on the manufacturer's own page or data sheet on the date given and is quoted as printed. Every gallon, quart and square-foot figure in this article was produced by the calculation engine behind this site's paint calculator on 2026-10-03.
- Sherwin-Williams, paint calculator page: "A gallon of paint typically covers about 350-400 square feet … A quart of paint covers 100 square feet". https://www.sherwin-williams.com/en-us/color/color-tools/paint-calculator (accessed 2026-09-09)
- Glidden (PPG), paint calculator page: "1 gallon of paint typically covers up to 400 sq. ft. on primed, smooth, non-porous surfaces." https://www.glidden.com/paint-calculator (accessed 2026-09-09)
- Behr, Premium Plus interior product page: "250-400 Sq. Ft. Coverage per Gallon" (accessed 2026-09-09)
- Benjamin Moore, Regal Select 550 technical data sheet: two coats are required on new or bare surfaces; previously painted surfaces can be finished with 1 or 2 coats. (accessed 2026-09-07)