How many cubic yards of concrete for a 10x10 slab at 4 inches?

About 1.23 cubic yards (33.33 cu ft ÷ 27). With a 10% waste allowance that becomes roughly 1.36 yards, so ordering 1.5 cubic yards is the safe move.

How many cubic yards for a 10x10 slab at 6 inches?

About 1.85 cubic yards (50 cu ft ÷ 27). With waste, round up to 2 cubic yards — at this point ready-mix delivery is almost always the cheapest option.

Should I order ready-mix or use bags for a 10x10 slab?

At 4 inches thick (1.23 cubic yards), both work: about 56 eighty-pound bags or a 1.5-yard ready-mix order. Once the slab approaches 2 cubic yards, ready-mix is usually cheaper and far less labor.

How do you convert cubic feet to cubic yards?

Divide cubic feet by 27, since one cubic yard equals 27 cubic feet (a 3 ft × 3 ft × 3 ft cube). For example, 33.33 cu ft ÷ 27 ≈ 1.23 cubic yards.

Is there a minimum order for ready-mix concrete?

Most suppliers have a 1-cubic-yard minimum, and many charge a short-load fee for orders under 2–3 yards. A 10 × 10 slab at 4 inches (1.23 yards) clears the minimum but may incur a small-load surcharge.

Guide

How Many Yards of Concrete Do I Need for a 10x10 Slab?

Ready-mix concrete is sold by the cubic yard, so knowing your slab in yards is what lets you order correctly. A 10 × 10 foot slab at 4 inches thick is 33.33 cubic feet — divide by 27 and you get 1.23 cubic yards. With a standard 10% waste allowance that becomes about 1.36 yards, so ordering 1.5 cubic yards covers you with a comfortable buffer.

Key Takeaways

A 10 × 10 ft slab at 4 inches thick is 33.33 cubic feet — 1.23 cubic yards.
With a 10% waste allowance that becomes about 1.36 cubic yards; order 1.5.
One cubic yard equals 27 cubic feet (3 ft × 3 ft × 3 ft).
Most ready-mix suppliers have a 1-cubic-yard minimum order, so a 10 × 10 slab qualifies.
Around 2 cubic yards, ready-mix delivery usually beats bagged concrete on price and labor.

Calculate Your Concrete

How to Calculate Cubic Yards for a 10x10 Slab

Cubic yardage comes from the slab volume in cubic feet divided by 27. The waste allowance is applied after the conversion, since you order yards, not feet.

1Measure the slab: 10 ft long × 10 ft wide, and decide the thickness (4 inches is standard for patios).
2Convert thickness to feet: 4 ÷ 12 = 0.333 ft.
3Calculate cubic feet: 10 × 10 × 0.333 = 33.33 cu ft.
4Convert to cubic yards: 33.33 ÷ 27 ≈ 1.23 cu yd.
5Add a 10% waste allowance: 1.23 × 1.10 ≈ 1.36 cu yd — round your order up to 1.5 cubic yards.

The Cubic Yard Formula

Concrete volume starts in cubic feet because slabs are measured in feet and inches. Dividing by 27 converts cubic feet to cubic yards, since one cubic yard is a 3 ft × 3 ft × 3 ft cube (27 cubic feet).

Cubic yards = Length (ft) × Width (ft) × Thickness (ft) ÷ 27

Worked Example: 10 ft × 10 ft Slab at 4 Inches

Here is the full calculation for the classic 10 × 10 patio slab at 4 inches thick, plus the yardage for a 6-inch pour.

Step 1

Slab dimensions: 10 ft × 10 ft, 4 inches thick.

Step 2

Thickness in feet: 4 ÷ 12 = 0.333 ft.

Step 3

Volume: 10 × 10 × 0.333 = 33.33 cubic feet.

Step 4

Cubic yards: 33.33 ÷ 27 ≈ 1.23 cubic yards.

Step 5

With 10% waste: 1.23 × 1.10 ≈ 1.36 cubic yards.

Step 6

Order: round up to 1.5 cubic yards for a safe buffer.

Slab thickness	Cubic feet	Cubic yards
4 in	33.3	1.23
6 in	50.0	1.85

Common Mistakes

Ordering the exact calculated yardage with no waste buffer — short loads cost more in redelivery fees than the extra concrete would have.
Mixing up cubic feet and cubic yards — forgetting to divide by 27 over-orders by 27×.
Entering thickness in inches without converting to feet first.
Ignoring the supplier minimum — most ready-mix plants charge for a full yard minimum per load.
Comparing bag math to ready-mix quotes without converting both to cubic yards first.

Practical Tips

Round your order up to the nearest half yard — 1.5 is the right call for this slab.
Ask the supplier about short-load fees before ordering under 2 yards.
Have the subgrade compacted and forms level before the truck arrives — the clock starts at the plant.
Add control joints to a 10 × 10 slab to manage cracking as the concrete cures.
Use the NOVORY Concrete Calculator to double-check your yardage before you call the supplier.