How Much Concrete for a Patio? Yards by Size

How much concrete for a patio comes down to a handy rule: at the usual 4-inch thickness, every 100 square feet of patio takes about 1.23 cubic yards. A 12x16 patio needs about 2.4 yards, and a 16x20 patio needs about 4 yards. The table below covers common sizes, and the sections after it explain how to adjust for odd shapes, thicker edges, and an old patio that has to come out first.

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Concrete for common patio sizes at 4 inches

Patio size	Square feet	Cubic yards	Order with ~8% extra
10 x 12	120	1.48	1.6
12 x 12	144	1.78	1.9
12 x 16	192	2.37	2.6
14 x 16	224	2.77	3.0
16 x 20	320	3.95	4.25
20 x 20	400	4.94	5.25

For a 5-inch patio, multiply the cubic yards by 1.25. For 6 inches, multiply by 1.5.

Odd shapes

Patios are often L-shaped, rounded, or wrapped around a corner of the house.

L-shape: split it into two rectangles, figure each, and add them.
Circle: area = 3.14 × radius × radius. A 14-foot round patio has a 7-foot radius and an area of about 154 square feet, or 1.9 cubic yards at 4 inches.
Curved edge on a rectangle: figure the rectangle, then add or subtract a rough half-circle for the curve. A few square feet either way rarely changes the order much.

Thickness and edges

Four inches is standard for a patio carrying people, furniture, and a grill. Many installers thicken the outer edge to 6 or 8 inches over a width of about 6 to 8 inches. That stiffens the edge where it is most likely to crack and helps where the ground slopes away. On a 16x20 patio, a 6-inch-wide edge that drops 4 extra inches adds about 72 × 0.5 × 0.333 = 12 cubic feet, or roughly 0.45 cubic yards.

A hot tub, outdoor kitchen, or masonry fireplace usually calls for a thicker section under it. Follow the maker’s guidance and size those areas separately.

Base, slope, and joints

Base: 4 inches of compacted crushed stone is common. Per 100 square feet, that is about 1.23 cubic yards, or roughly 1.7 to 1.85 tons.
Slope: plan for about 1/8 to 1/4 inch of fall per foot away from the house so rain does not run toward the foundation.
Joints: on a 4-inch slab, control joints every 8 to 10 feet are a common target, with panels kept close to square. An isolation joint goes where the patio meets the house.

Taking out an old patio first

If a cracked concrete or brick patio is coming out, plan for the weight of the tear-out. Old concrete runs about 4,000 pounds per cubic yard in place, so a 4-inch patio of 200 square feet can produce roughly 2.5 cubic yards and close to 5 tons of rubble. Many landfills and recyclers take clean concrete at lower rates than mixed trash; Dumpmapper’s concrete disposal guide lists what sites usually ask for.

Concrete, pavers, or asphalt?

Poured concrete is often the least expensive hard patio per square foot. Pavers cost more up front but are easier to repair one piece at a time. Asphalt is unusual for patios because it softens in direct sun; see asphalt patio for when it can work.

Questions people ask

How much concrete do I need for a 12x16 patio?

About 2.37 cubic yards at 4 inches thick. With a waste cushion, most people order around 2.5 to 2.75 yards.

How thick should a concrete patio be?

Four inches on a compacted base is standard. Thicken the edges or specific areas for hot tubs, kitchens, or heavy features.

How many bags of concrete for a 10x10 patio?

About 56 bags of 80-pound mix at 4 inches thick, based on roughly 0.6 cubic feet per bag.

Which way should a patio slope?

Away from the house, usually about 1/8 to 1/4 inch per foot, so water drains off the slab instead of toward the foundation.

How much gravel goes under a patio?

About 1.23 cubic yards per 100 square feet for a 4-inch base, or roughly 1.7 to 1.85 tons.

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