Material Coverage Reference

Almost nothing is sold in the unit you measured. You work out a room in square feet and the shelf offers you bags, boxes, sheets, rolls, gallons and bundles. The figure that closes that gap — what one package actually covers — is the number this page collects.

Every figure below is the one the matching calculator uses, and this page is generated from those calculators rather than typed alongside them, so the two cannot drift apart. Where a range is given, it is because the real answer depends on something: the texture of the wall, the notch on your trowel, the depth you spread it at.

The figure on the package you are holding always wins. These are standard sizes and typical rates for planning. Check the bag before you divide.

The ones people look up most

Question	Answer	Work it out
One gallon of paint	350 sq ft, one coat, on a typical wall	Paint calculator
One 80 lb bag of concrete	0.6 cu ft — 45 bags to a cubic yard	Concrete slab calculator
One 4 × 8 ft sheet of drywall	32 sq ft	Drywall calculator
One 2 cu ft bag of mulch	12 sq ft at 2 in. deep, 8 at 3 in.	Mulch calculator
One bundle of shingles	a third of a square — 3 bundles cover 100 sq ft	Roof shingles calculator
One 50 lb bag of thinset	about 95 sq ft with a 1/4 in. notch trowel	Tile calculator
One 12 × 12 in. tile	exactly 1 sq ft — 144 sq in. ÷ 144	Tile calculator
One pallet of sod	450 sq ft on the common US pallet	Sod calculator

Each row links to the calculator that uses that figure, which will do the division for you.

Paint and primer

Paint coverage is the most optimistic number in the building trade. "Up to 400 square feet per gallon" is measured on a smooth, sealed, primed surface by somebody who does it for a living. Texture is the variable nobody accounts for — a textured wall has more actual surface than its measured area, which is what texture means.

Surface	Per gallon, one coat
Smooth, previously painted	400 sq ft
Typical wall	350 sq ft
Textured or porous	300 sq ft
Primer on bare drywall	200–300 sq ft
Rough masonry, block, stucco	150–200 sq ft

Multiply by the number of coats. Two coats is standard; three over bare board or a color change.

Opening	Deduct
A standard door	about 21 sq ft
A standard window	about 12 sq ft

Under about 20 sq ft, do not deduct at all — the waste from cutting around it eats the difference.

Drywall, compound and tape

Sheet	Covers
4 × 8 ft	32 sq ft
4 × 10 ft	40 sq ft
4 × 12 ft	48 sq ft

On a wall longer than 8 ft, 12 ft sheets mean one butt joint instead of two — less compound and far less sanding.

What else	How much
Screws	about 32 per sheet
Joint compound	roughly 1 gallon per 105 sq ft, over three coats
Joint tape	about 0.4 linear ft per sq ft of board

All three come out of the drywall calculator along with the sheets.

Tile, thinset and grout

Tile face area is square inches divided by 144. That division is the single most common arithmetic mistake in material estimating — get it wrong and you can be out by a factor of two.

Tile	Each covers
3 × 6 in. subway	0.125 sq ft
4 × 12 in.	0.33 sq ft
12 × 12 in.	1 sq ft
12 × 24 in.	2 sq ft
18 × 18 in.	2.25 sq ft
24 × 24 in.	4 sq ft

Boxes vary far more than tiles do. Two boxes of 12 × 12 from different makers can hold 15 sq ft and 11.

Material	Coverage
Thinset, 50 lb bag	95 sq ft at a 1/4 in. square-notch trowel
Thinset, 12 in. tile	about 60 sq ft — bigger notch, less coverage
Thinset, large format	about 40 sq ft — 1/2 in. notch

The trowel notch decides thinset coverage, not the bag. The same shower can need two bags or four.

Grout is the figure that varies most, because it depends on joint length rather than area. Big tiles with narrow joints use very little; mosaic uses several times as much over the same floor.

Tile	Grout	Per 10 lb bag
12 in. and up, 1/8 in. joints	about 1 lb per 9 sq ft	about 90 sq ft
6 in., 1/8 in. joints	about 1 lb per 5 sq ft	about 50 sq ft
3 × 6 in. subway, 1/16 in.	about 1 lb per 5 sq ft	about 50 sq ft
Mosaic sheets	about 1 lb per 2.5 sq ft	about 25 sq ft

This is why the shower calculator allows roughly double the plain-floor rate — a shower has a mosaic pan and a niche, so far more joint length per square foot.

Flooring, carpet and wallpaper

Material	Coverage
Laminate, per box	usually 18–24 sq ft
Vinyl plank, per box	often 24–30 sq ft
Underlayment roll	100 sq ft
Carpet roll — 12 ft	the standard
Carpet roll — 15 ft	less common, fewer seams
Carpet roll — 13.5 ft (4 m)	imported

Carpet is bought by the linear yard off a fixed-width roll, so the waste is set by the room, not by a percentage. A linear yard of 12 ft goods is 36 sq ft.

Wallpaper roll	Size
US double roll	27 in. wide × 27 ft
European roll	20.5 in. wide × 33 ft
US single roll	27 in. wide × 13.5 ft

The pattern repeat, not the roll size, is what usually decides how many you need.

Concrete

Concrete is sold by the cubic yard on a truck and by the cubic foot in a bag, and the two are far apart: a cubic yard is 27 cubic feet. Somewhere around one cubic yard is where ready-mix starts winning on both price and effort.

Bag	Yields	Per cubic yard
80 lb	0.6 cu ft	45 bags
60 lb	0.45 cu ft	60 bags
50 lb	0.375 cu ft	72 bags
40 lb	0.3 cu ft	90 bags

Forty-five 80 lb bags is over a ton of material to lift, open and mix before the first batch starts going off.

Mulch, gravel and topsoil

Loose material is sold by volume but spread to a depth, and depth is the measurement people estimate. Plan two inches and spread three and you are 50% short before you finish the first bed.

Bag	At 2 in. deep	At 3 in.	At 4 in.
2 cu ft	12 sq ft	8 sq ft	6 sq ft
3 cu ft	18 sq ft	12 sq ft	9 sq ft
1.5 cu ft	9 sq ft	6 sq ft	4.5 sq ft

A cubic yard is 27 cu ft — thirteen and a half of the standard 2 cu ft bags.

Aggregate	Weight
Crushed stone / #57	about 1.4 tons per cu yd
Pea gravel	about 1.35 tons per cu yd
Crusher run / road base	about 1.5 tons per cu yd
River rock	about 1.25 tons per cu yd
Decomposed granite	about 1.3 tons per cu yd

Suppliers often quote by the ton and you calculated in cubic yards. Ask them to convert rather than doing it yourself.

Roofing

A roof is always bigger than the house under it. Multiply the flat footprint by the pitch multiplier to get the true sloped area — it is pure geometry, with no allowance built in.

Pitch	Multiplier	1,500 sq ft footprint becomes
3/12	1.031	1,546 sq ft
4/12	1.054	1,581 sq ft
5/12	1.083	1,624 sq ft
6/12	1.118	1,677 sq ft
7/12	1.158	1,737 sq ft
8/12	1.202	1,803 sq ft
9/12	1.250	1,875 sq ft
10/12	1.302	1,953 sq ft
12/12	1.414	2,121 sq ft

Material	Coverage
Shingle bundle	a third of a square — 3 bundles per 100 sq ft
Roofing nails	about 320 per square
Starter strip roll	about 100 linear ft
Shingle underlayment roll	4 squares
Metal roof screws	about 80 per square
Synthetic underlayment roll	1000 sq ft

Metal panel	Covers
36 in.	standard exposed fastener
24 in.	standing seam
16 in.	narrow standing seam
26 in.	corrugated, after overlap
12 in.	narrow architectural

Coverage width, not sheet width. A 39 in. sheet usually covers 36 once it laps its neighbor — order on the sheet width and you will be about 8% short.

Framing and insulation

Stud spacing	Why
16 in. on center	standard
24 in. on center	advanced framing
12 in. on center	heavy load

Sheet goods come in 4 ft widths, and 48 divides evenly by 16 and by 24. That is the whole reason.

Blown insulation	R-value and bag
Blown cellulose	R-3.5 per inch, 16 cu ft per bag
Blown fiberglass	R-2.5 per inch, 40 cu ft per bag

R-value is cumulative — four inches at R-3.5 per inch gives you R-14. Recommended attic levels run from about R-30 in the far south to R-60 in the north.

Lawn

Sod	Covers
450 sq ft	the common US pallet
500 sq ft
400 sq ft
Big roll	2 × 5 ft (10 sq ft)
Slab	16 × 24 in. (2.67 sq ft)
Small roll	1.5 × 3.3 ft (5 sq ft)

Grass seed, new lawn	Per 1,000 sq ft
Tall fescue	7 lb per 1,000 sq ft
Perennial ryegrass	7.5 lb
Kentucky bluegrass	2.5 lb
Fine fescue	4.5 lb
Bermuda (hulled) or Zoysia	1.5 lb
Cool season blend	5 lb

Halve these for overseeding. Rates differ this much because seed size does — there are roughly two million Kentucky bluegrass seeds in a pound and about 220,000 tall fescue.

Also	Rate
Starter fertilizer	about 5 lb per 1,000 sq ft
Straw	one bale per 750 sq ft — thin enough to still see soil

The four conversions that cost money

Almost every serious over- or under-order comes from a unit, not a measurement.

Trap	The conversion	What it looks like when you get it wrong
Square inches are not square feet	divide by 144	A 4 × 8 in. paver is 32 sq in. ÷ 144 = 0.22 sq ft. Read it as 0.44 and you order half a patio.
Cubic feet are not cubic yards	divide by 27	A cubic yard is 27 cu ft — 13.5 standard mulch bags, or 45 bags of 80 lb concrete.
Linear yards are not square yards	multiply by the roll width ÷ 3	A linear yard of 12 ft carpet is 4 square yards. Two quotes in different units are not comparable.
Weight is not volume	ask the supplier to convert	A ton of gravel is roughly 0.7 cubic yards, and it varies with the stone.

Masonry

Brick and block are sized so that the unit plus its mortar joint comes to a round number.

Unit	Face with 3/8 in. joint	Per sq ft	Mortar
Modular brick	8 × 2 5/8 in. — 21 sq in.	6.86	One 80 lb bag lays about 33
Standard brick	8 3/8 × 2 5/8 in. — 22 sq in.	6.55	About 35 to a bag
Queen brick	8 × 3 1/8 in. — 25 sq in.	5.76	About 40 to a bag
King brick	10 × 3 in. — 30 sq in.	4.8	About 47 to a bag
Utility brick	12 × 4 in. — 48 sq in.	3	About 75 to a bag
Concrete block, 8 × 16 face	8 × 16 in. — 128 sq in.	1.125	One 80 lb bag lays about 12
Long block, 8 × 24 face	8 × 24 in. — 192 sq in.	0.75	About 8 to a bag

Divide 144 by the face area in square inches. Block thickness does not change the count — a 6 in. and an 8 in. block cover the same wall.

Job	Figure	Where it comes from
Filling 8 in. block cores, all of them	about 1.1 cu yd per 100 sq ft of wall	A hollow block is a little over half solid
Filling every fourth core	about 0.37 cu yd per 100 sq ft	Rebar at 32 in. centers
Brick veneer wall ties	one per 2.67 sq ft	16 in. vertical × 24 in. horizontal
Weight of a single-wythe brick wall	about 40 lb per sq ft of face	Before the footing carries it

Cladding and boards

Coverage is exposure × length ÷ 12. The lapped edge does no covering.

Product	Actual width	Exposed	One 12 ft piece covers
1 × 4 shiplap	3 1/2 in.	3 1/8 in.	3.13 sq ft
1 × 6 shiplap	5 1/2 in.	5 in.	5.00 sq ft
1 × 6 nickel gap	5 1/2 in.	5 1/8 in.	5.13 sq ft
1 × 8 shiplap	7 1/4 in.	6 7/8 in.	6.88 sq ft
1 × 8 tongue and groove	7 1/4 in.	7 in.	7.00 sq ft
5 1/4 in. fiber cement siding	5 1/4 in.	4 in.	4.00 sq ft
6 1/4 in. fiber cement siding	6 1/4 in.	5 in.	5.00 sq ft
7 1/4 in. fiber cement siding	7 1/4 in.	6 in.	6.00 sq ft
8 1/4 in. fiber cement siding	8 1/4 in.	7 in.	7.00 sq ft
9 1/4 in. fiber cement siding	9 1/4 in.	8 in.	8.00 sq ft
12 in. fiber cement siding	12 in.	10 3/4 in.	10.75 sq ft

Anything that laps covers its exposed face, not its width. Calculate on the width and you will be roughly ten per cent short.

Unit	What it is	Note
Square	100 sq ft	How siding and roofing are both sold and quoted
Board foot	144 cubic inches	Thickness in. × width in. × length ft ÷ 12
4/4 hardwood	a nominal 1 in. rough	Surfaces to about 13/16 in. — you pay for the full inch

Rainwater and decks

Part	Size	Handles
K-style gutter	5 in.	5,520 sq ft of effective drainage area
K-style gutter	6 in.	7,960 sq ft
Downspout	2 × 3 in. — 6 sq in.	600 sq ft of roof
Downspout	3 in. round — 7.1 sq in.	706 sq ft of roof
Downspout	3 × 4 in. — 12 sq in.	1,200 sq ft of roof
Downspout	4 in. round — 12.6 sq in.	1,255 sq ft of roof

One square inch of downspout per 100 sq ft of roof. Effective area is the roof footprint multiplied by a pitch factor, not the sloped surface — rain falls vertically.

Deck joist	12 in. centers	16 in. centers	24 in. centers
2 × 6 southern pine	9 ft 11 in.	9 ft 0 in.	7 ft 7 in.
2 × 8 southern pine	13 ft 1 in.	11 ft 10 in.	9 ft 8 in.
2 × 10 southern pine	16 ft 2 in.	14 ft 0 in.	11 ft 5 in.
2 × 8 hem-fir or SPF	12 ft 6 in.	10 ft 11 in.	8 ft 11 in.
2 × 10 hem-fir or SPF	15 ft 8 in.	13 ft 7 in.	11 ft 1 in.

IRC 2021 Table R507.6, 40 psf live plus 10 psf dead, no cantilever. Span is the clear distance between supports, not the length of the board.

Deck surface	Semi-transparent stain	Solid stain
Smooth, previously sealed	250–300 sq ft/gal	300–400 sq ft/gal
Normal, a few seasons old	200–250 sq ft/gal	250–300 sq ft/gal
Rough sawn	150–200 sq ft/gal	175–250 sq ft/gal
Weathered gray, bare	100–150 sq ft/gal	150–200 sq ft/gal

A spindle railing has roughly four times the surface of the rectangle it occupies, and routinely needs more stain than the deck it surrounds.

Where these come from

Bag yields, sheet sizes and package counts come from published manufacturer product data. Spread rates come from the same, at the stated trowel notch or surface type. Spacing and code figures come from the International Residential Code. Each calculator names the specific sources it relies on at the foot of its own page, and how we check the numbers explains what happens before any of it goes live.

If a figure here does not match the package in your hand, the package is right and we would like to know — tell us and we will check it against the source and correct the page.