How many 80-lb bags of concrete for a 10x10 slab?

A 10 × 10 ft slab at 4 inches thick needs about 56 eighty-pound bags (33.3 cu ft ÷ 0.6 cu ft per bag). Add 5–10% extra for waste, which brings it to roughly 59–62 bags.

How many 60-lb bags of concrete for a 10x10 slab?

About 75 sixty-pound bags for a 10 × 10 ft slab at 4 inches thick (33.3 cu ft ÷ 0.45 cu ft per bag), before a 5–10% waste allowance.

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

Bagged concrete is practical for a 10 × 10 slab at 4 inches (about 1.24 cubic yards). Once a project approaches 2 cubic yards or more, ready-mix delivery is usually cheaper and far less labor.

How thick should a 10x10 concrete slab be?

Four inches is standard for patios, walkways, and shed floors. Use 5–6 inches for driveways or slabs that will carry vehicles.

How much does an 80-lb bag of concrete yield?

A standard 80-lb bag yields about 0.6 cubic feet of mixed concrete, and a 60-lb bag yields about 0.45 cubic feet. Yields vary by product, so confirm on the bag before calculating.

Guide

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

A 10 × 10 foot slab is one of the most common DIY concrete projects — a patio, a shed base, or a walkway pad. At the standard 4-inch thickness it takes about 1.24 cubic yards of concrete, which works out to 56 eighty-pound bags or 75 sixty-pound bags. This guide shows the exact math, a thickness chart, and when bags stop making sense versus ready-mix.

Key Takeaways

A 10 × 10 ft slab at 4 inches thick needs about 1.24 cubic yards of concrete.
That equals 56 eighty-pound bags or 75 sixty-pound bags — before waste.
An 80-lb bag yields about 0.6 cu ft; a 60-lb bag yields about 0.45 cu ft.
Add 5–10% extra for spillage, uneven subgrade, and broken bags.
For pours over roughly 2 cubic yards, ready-mix delivery is usually cheaper than bags.

Calculate Your Concrete

How to Calculate Bags for a 10x10 Slab

Bag count comes from the slab volume divided by the yield of one bag. Work in cubic feet throughout, because bag yields are stated in cubic 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 = 33.3 cu ft.
4Convert to cubic yards: 33.3 ÷ 27 ≈ 1.24 cu yd (useful when comparing against ready-mix).
5Divide cubic feet by the yield per bag: 33.3 ÷ 0.6 ≈ 56 eighty-pound bags.

The Bag Count Formula

Bagged concrete is sold by weight, but what matters is yield — the volume of mixed concrete each bag produces. A standard 80-lb bag yields about 0.6 cubic feet and a 60-lb bag yields about 0.45 cubic feet. Always check the yield printed on the specific product, since it varies by manufacturer.

Bags needed = Volume (cu ft) ÷ Yield per bag (cu ft)

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 a chart for other thicknesses.

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 = 33.3 cubic feet.

Step 4

Cubic yards: 33.3 ÷ 27 ≈ 1.24 cubic yards.

Step 5

Eighty-pound bags: 33.3 ÷ 0.6 = 55.5 → round up to 56 bags.

Step 6

Sixty-pound bags: 33.3 ÷ 0.45 = 74.1 → round up to 75 bags.

Slab thickness	Cubic yards	80-lb bags	60-lb bags
3 in	0.93	42	56
4 in	1.24	56	75
5 in	1.54	70	93
6 in	1.85	84	112

Common Mistakes

Using 80-lb bag math for 60-lb bags (or vice versa) — the yields differ by about 33%.
Forgetting the waste allowance — order 5–10% extra for spillage and uneven ground.
Assuming every bag yields the same volume — check the yield printed on the bag.
Ordering the exact calculated count with no buffer for broken or short bags.
Mixing bag sizes mid-project, which makes tracking the total harder than it needs to be.

Practical Tips

Round up, never down — coming up half a bag short mid-pour is worse than having one bag left over.
Stage the bags near the pour site before you start mixing to keep the work flowing.
For slabs thicker than 6 inches or larger than about 2 cubic yards, price ready-mix delivery — it is often cheaper than bags.
Add control joints to a 10 × 10 slab to manage cracking as the concrete cures.
Use the NOVORY Concrete Calculator to double-check your bag count before you buy.