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How Much Concrete for a 16x40 Driveway?

For a 16x40 driveway poured 5 inches thick, plan on about 9.88 cubic yards of concrete. That comes from 640 square feet times 0.417 feet of depth, divided by 27. How much concrete for a 16x40 driveway at other thicknesses is in the table below.

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The math for a 16x40 driveway

  1. Area: 16 ft × 40 ft = 640 sq ft.
  2. Thickness in feet: 5 in ÷ 12 = 0.417 ft.
  3. Volume: 640 × 0.417 = 266.7 cubic feet.
  4. Cubic yards: 266.7 ÷ 27 = 9.88 yd³.
  5. With 10% extra: 10.86 yd³.

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

Concrete for a 16x40 driveway by thickness

ThicknessCubic feetCubic yardsYards +10%80 lb bags60 lb bags
4 in213.37.908.69356475
5 in266.79.8810.86445593
6 in320.011.8513.04534712

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

Choosing the thickness

Residential concrete driveways are usually 4 to 6 inches thick. Five inches is a sensible minimum if a pickup or delivery truck uses it, and 6 inches if heavier vehicles or an RV park on it. The apron at the street often gets the thicker section.

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 driveway.

Base and forms

Prep matters as much as the yardage. Strip sod and soft soil, compact the subgrade, then add a compacted stone base, commonly about 4 inches. A level, firm base also keeps your thickness even, which keeps the yardage close to the math.

Joints, mesh and rebar

Cut or tool control joints so the slab cracks where you want it to. A common rule is spacing them, in feet, at no more than two to three times the slab thickness in inches, so about 12 feet apart for a 4-inch slab, and about a quarter of the slab depth deep.

Questions people ask

How many yards of concrete for a 16x40 driveway at 4 inches?

About 7.90 cubic yards, or 8.69 with 10 percent extra.

How many yards for a 16x40 driveway at 6 inches?

About 11.85 cubic yards.

How many 80 lb bags for a 16x40 driveway?

About 356 bags at 4 inches thick, before any waste allowance.

How many square feet is a 16x40 driveway?

640 square feet.

Should I add extra for waste?

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

How thick should the base under the slab be?

About 4 inches of compacted gravel is common for residential slabs, more on soft or poorly drained soil.

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