Concrete for a 40 x 60 ft Slab

Everything for a 40 x 60 ft slab (2400 sq ft) — commercial pad: cubic yards at 4, 5 and 6 inches thick, bag counts, base gravel, rebar and cost.

Quick answer

A 40 x 60 ft slab at 6 inches thick needs 44.44 cubic yards of concrete (1200 cu ft). With 10% waste, order 49 yd³ of ready-mix — about $8,085 in material — or 2200 bags of 80 lb mix.

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Volume at each thickness

ThicknessCubic feetCubic yardsOrder (ready-mix)80 lb bags60 lb bagsWeight
4 in80029.6332.75 yd³1467195666 tons
5 in100037.0440.75 yd³1834244582.5 tons
6 in120044.4449 yd³2200293499 tons
Volumes include a 10% waste allowance; ready-mix rounds up to the next quarter yard.

volume = 40 ft x 60 ft x thickness/12  |  yd³ = ft³ / 27

At 6 in thick

Concrete to order

49yd³

44.44 yd³ before waste

80 lb bags

2200

Base gravel (4 in)

59.4tons

Compacted crushed stone

#4 rebar at 16 in

187sticks

2497 lb, or 53 mesh sheets

Concrete cost

$8,085

At $165/yd³, before delivery

Pouring a 40 x 60 ft slab

At 2400 square feet this pour needs 49 yards, which is comfortably worth a ready-mix truck; mixing this by hand would be well over a hundred bags. Excavate for 4 inches of compacted base plus the slab thickness, and set forms to a slope of about 1/8 inch per foot away from any structure.

Control joints go in at one quarter of the slab depth, spaced no more than two to three times the thickness in inches converted to feet — for a 6 inch slab that is roughly every 15 feet. Keep the surface moist for seven days.

Source & method: Volumes are geometry (40 x 60 x thickness), bag counts use published nominal yields, weight uses 150 lb/ft³, and the gravel figure uses 135 lb/ft³ for compacted road base. Cost uses a $165/yd³ default — adjust it on the slab cost calculator.

Supplies for this slab

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Frequently asked questions

How much does a 40 x 60 ft concrete slab cost?
Concrete alone is about $8,085 at $165 per cubic yard, plus roughly $120 delivery. Add base gravel and reinforcement for materials near $12,502, or $22,102 installed with labor at $4 per square foot.
How thick should a 40 x 60 ft slab be?
4 inches for foot traffic — patios, shed floors and walkways. Step up to 5 or 6 inches where a vehicle will park or where you will store heavy equipment. Commercial pad is the typical use for this size.
How much rebar does a 40 x 60 ft slab need?
About 187 twenty-foot sticks of #4 bar for a 16 inch grid both ways — 3738 linear feet weighing 2497 lb. Welded wire mesh is the cheaper alternative at about 53 sheets.

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