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How Much Concrete for a 12x12 Patio?

For a 12x12 patio poured 4 inches thick, plan on about 1.78 cubic yards of concrete. That comes from 144 square feet times 0.333 feet of depth, divided by 27. How much concrete for a 12x12 patio at other thicknesses is in the table below.

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The math for a 12x12 patio

  1. Area: 12 ft × 12 ft = 144 sq ft.
  2. Thickness in feet: 4 in ÷ 12 = 0.333 ft.
  3. Volume: 144 × 0.333 = 48.0 cubic feet.
  4. Cubic yards: 48.0 ÷ 27 = 1.78 yd³.
  5. With 10% extra: 1.96 yd³.

The concrete calculator runs the same steps for any size and thickness.

Concrete for a 12x12 patio by thickness

ThicknessCubic feetCubic yardsYards +10%80 lb bags60 lb bags
4 in48.01.781.9680107
5 in60.02.222.44100134
6 in72.02.672.93120160

Bag counts assume about 0.60 cubic feet per 80 lb bag and 0.45 per 60 lb bag, rounded up.

How thick to pour it

Four inches is standard for a patio that sees foot traffic and furniture. Slope it about 1/8 to 1/4 inch per foot away from the house so rain runs off, and go thicker under a hot tub or outdoor kitchen.

Placing the order

Concrete is ordered by the cubic yard, and a yard is 27 cubic feet. Ready-mix plants usually sell in quarter- or half-yard steps, so round up to the next step rather than down. Running short in the middle of a pour leaves a cold joint, which is a weak seam in the patio.

Getting the ground ready

Uneven ground is the main reason pours run short. Every half inch of extra depth across the patio adds concrete you did not plan for. Screed the base flat, check it with a string line and set the forms to finished height before the truck arrives.

Joints and reinforcement

Reinforcement does not stop cracks, but it holds them tight. Wire mesh or rebar set mid-depth on chairs is common for a patio that carries vehicles; fiber-reinforced mix is an option for light-duty slabs. Joints about 8 feet apart control where cracks form.

Questions people ask

How many yards of concrete for a 12x12 patio at 4 inches?

About 1.78 cubic yards, or 1.96 with 10 percent extra.

How many yards for a 12x12 patio at 6 inches?

About 2.67 cubic yards.

How many 80 lb bags for a 12x12 patio?

About 80 bags at 4 inches thick, before any waste allowance.

How many square feet is a 12x12 patio?

144 square feet.

Should I add extra for waste?

Yes. Adding 5 to 10 percent covers uneven base, spillage and form bulges.

When is bagged concrete practical?

Usually for jobs under about a cubic yard. Beyond that, mixing dozens of bags by hand gets slow and batches may not blend well.

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