16 × 12 slab by thickness
Every figure includes 10% waste. Bag counts use the manufacturers' stated yields (0.6 cu ft per 80 lb bag, 0.45 per 60 lb).
| Thickness | Cubic yards | 80 lb bags | 60 lb bags | Bags cost | Ready-mix cost |
|---|---|---|---|---|---|
| 4 in | 2.61 | 118 | 157 | $708 to $944 | $389 to $645 |
| 5 in | 3.26 | 147 | 196 | $882 to $1,176 | $474 to $769 |
| 6 in | 3.91 | 177 | 235 | $1,062 to $1,416 | $558 to $893 |
| 8 in | 5.21 | 235 | 313 | $1,410 to $1,880 | $678 to $991 |
Patios this size are usually poured with a control joint down the middle so the slab cracks where you tell it to instead of where it wants.
Building a 16 × 12 slab
A 12 × 16 patio is where slope and joints start to matter. Slope the whole slab 1/8 inch per foot away from the house, which is 2 inches of fall across 16 feet: set the far form 2 inches lower than the house side and check it with a string line. Cut one control joint across the 16-foot direction at 8 feet so you end up with two 8 × 12 panels. The rule is a joint every 8 to 12 feet on a 4-inch slab, and the single midpoint joint satisfies it in both directions here. Mesh on chairs, 4 inches of compacted gravel, and a 1/2-inch expansion strip at the foundation.
Pour day at this size
This is a truck pour for most people. Have the driver put the chute at the far end and work back toward the house so nobody walks through placed concrete. Rake, screed, bull float, then wait for the bleed water to leave before edging and the final finish. If the patio gets afternoon sun, pour in the morning; a slab this size can set faster than two people can finish it.
Joint spacing and depth follow ACI 302.1R (joints every 24 to 36 times the slab thickness, cut one quarter deep); anchor bolt spacing follows IRC R403.1.6; load figures come from manufacturers' published weights. Local code wins where it differs.
Having it poured instead
Contractors charge about $6 to $12 per square footfor a finished 4-inch slab in 2026, which puts a 16 × 12 slab at$1,152 to $2,304 installed. That covers forming, gravel base, pour, and finish; thicker slabs, reinforcement, and site prep on sloped or hard-to-reach ground push it toward the top of the range.
How we get these numbers
Volume is length × width × thickness in cubic feet, divided by 27, plus 10% waste. Bag yields come from the manufacturers' technical data sheets. Ready-mix runs $130 to $190per yard delivered, with a $50 to $150short-load fee under 5 yards at most plants. Prices refreshed at least twice a year (last: September 2026). Sources:
- Concrete Network: Concrete Prices 2026, How Much Is a Yard of Concrete?
- Angi: Concrete Cost Per Yard (2026)
- The Home Depot: Quikrete 80 lb Concrete Mix (bag yield and price)
- Estimators.us: Concrete Slab Cost in 2026, $6 to $12 per sq ft
- CalcShed: Concrete Slab Cost in 2026, per sq ft and by state
Frequently asked questions
How many bags of concrete for a 12x16 slab?
At 4 inches thick, 118 bags of 80 lb mix or 157 bags of 60 lb mix, including 10% extra for waste. That is 2.61 cubic yards of concrete.
How much does a 12x16 concrete slab cost?
Poured by a contractor, about $1,152 to $2,304 at 2026 rates of $6 to $12 per square foot for a 4-inch slab, including forming, pouring, and finishing. Doing it yourself, the concrete alone is $708 to $944 in bags or $389 to $645 delivered by truck, plus forms, gravel, and reinforcement.
How thick should a 12x16 slab be?
4 inches for a standard backyard patio. Go to 5 or 6 inches if vehicles will park on it, and use wire mesh or rebar in any slab that carries a load.
Where do the control joints go on a 12 × 16 patio?
One joint across the middle of the long side, at 8 feet, cut to a quarter of the slab depth, so 1 inch deep on a 4-inch slab. That gives two 8 × 12 panels, inside the 8 to 12 foot spacing a 4-inch slab wants. Saw it within 6 to 18 hours of the pour, or tool it in while the concrete is still plastic.
How much slope does a 12 × 16 patio need?
An eighth of an inch per foot away from the house, so 2 inches over 16 feet. Less than that and water sits against the foundation; more than 1/4 inch per foot and furniture starts to feel it.
Other common slab sizes
- 10 × 10 slab (a shed base, a small patio, or a hot tub pad)
- 12 × 12 slab (a patio, a larger shed, or a carport pad)
- 20 × 16 slab (a large patio or a workshop floor)
- 20 × 20 slab (a one-car garage floor or a driveway apron)
- 24 × 24 slab (a two-car garage floor)