How Many Bags of Concrete for a 10x10 Slab? (All Thicknesses)

Answer first: a 10x10 ft slab at 4 inches deep needs about 56 bags of 80 lb concrete with 10% waste factored in. That is 1.23 cubic yards of concrete.

Bag Count by Thickness

Thickness	Cubic yards	80 lb bags	60 lb bags	40 lb bags
2 inches	0.62 yd³	29 bags	38 bags	57 bags
3 inches	0.93 yd³	42 bags	56 bags	84 bags
4 inches	1.23 yd³	56 bags	74 bags	111 bags
5 inches	1.54 yd³	70 bags	93 bags	139 bags
6 inches	1.85 yd³	84 bags	112 bags	168 bags

All counts include 10% waste factor. Standard bag yields:

80 lb bag = 0.60 cubic feet
60 lb bag = 0.45 cubic feet
40 lb bag = 0.30 cubic feet

How the Math Works

A 10×10 ft slab at 4 inches:

Volume = 10 × 10 × (4/12) = 33.33 cubic feet
With 10% waste = 36.67 cubic feet = 1.23 cubic yards

Bags needed (80 lb at 0.60 ft³):
36.67 ÷ 0.60 = 61.1 → round up to 62 bags

Pallet check: 42 bags per standard pallet → 1.5 pallets

Why do different sources show different numbers? Bag yield varies by mix design. Quikrete 80 lb bags yield 0.60 cu ft; Sakrete 80 lb bags yield 0.60 cu ft; fast-setting mixes can yield slightly less. Always check the label on the bag you are buying.

Common Bag Brands and Yields

Brand	Weight	Yield	Bags per yd³
Quikrete 5000	80 lb	0.60 ft³	45 bags
Quikrete Fast-Setting	80 lb	0.60 ft³	45 bags
Sakrete	80 lb	0.60 ft³	45 bags
Quikrete	60 lb	0.45 ft³	60 bags
Quikrete	40 lb	0.30 ft³	90 bags

With 10% waste: plan on 50 bags, 66 bags, or 99 bags per cubic yard for 80, 60, and 40 lb bags respectively.

10x10 Slab: Bags vs Ready-Mix

For a 10×10 at 4 inches (1.23 yd³), here is the comparison:

Option	Cost estimate	Notes
56 bags × $7 (80 lb)	~$392 materials	Plus rental mixer, labor
Ready-mix delivery	~$350–$450 for 1.5 yd³ min	May have short-load fee

Rule of thumb: if your project is under 1 cubic yard, bags are almost always more practical. At 1–2 yards, compare the total delivered cost including short-load fees. Above 2 yards, ready-mix is usually cheaper.

A standard ready-mix truck minimum is typically 3 yards. For a 1.23 yd³ slab, you would pay for the unused yards unless a local supplier offers mini-mix or volumetric delivery.

Does a 10x10 Slab Need Rebar?

For a simple patio or shed base at 4 inches, fiber mesh (added to the mix) is often sufficient. For a driveway pad, vehicle parking, or anything structural, add rebar:

#4 rebar at 18-inch spacing is standard for residential driveways
A 10×10 pad needs about 7 bars each direction = 14 bars total at 10 ft each = 140 linear feet
Add 10% for overlap = about 154 linear feet of #4 rebar

Use the Calculator

For custom dimensions, different thicknesses, or metric measurements, use the concrete bag calculator or the concrete slab calculator for a full estimate including bags, cost, ready-mix comparison, and quote scope checks.