Concrete Coverage Calculator

Work out how much area your bags or yards of concrete will cover at a given thickness.

I have

Bag product

Number of bags

= 10 bags, 6 ft³ of concrete

Thickness

= 4 in

Covers about

18ft²

6 ft³ (0.22 yd³) of concrete at 4 in thick.

Sizes that fit

4 ft 6 in × 4 ft at 4 in
6 ft × 3 ft at 4 in

10 80 lb bags cover about 18 ft² at 4 in, for example a 4 ft 6 in × 4 ft pad. Sizes are rounded down so each fits; order a little extra for waste and uneven ground.

When to use this

Use it when you already have concrete and want to know what it'll do: leftover bags in the garage, a partial pallet, or the volume left on a ready-mix order. Pick the bag size and count (or enter a volume), set the thickness, and the calculator shows the area plus a few slab sizes that fit inside it.

Going the other way, from a size to the bags you need? Use the concrete calculator.

How coverage is calculated

Volume = number of bags × yield per bag, from the manufacturer's data sheet. Area = volume ÷ thickness, with the thickness in the same unit. One 80-lb bag yields 0.60 ft³; at 4 in (0.3333 ft) it covers 0.60 ÷ 0.3333 = 1.8 ft².

The example sizes are rounded down, so each one fits inside the area you have. Real pours lose a little to uneven ground, so don't plan to the last square foot.

Coverage chart

Square feet covered at each thickness, with no allowance for waste.

Area covered (ft²) by thickness
Concrete	2 in	3 in	4 in	5 in	6 in
40 lb bag	1.8	1.2	0.9	0.72	0.6
60 lb bag	2.7	1.8	1.35	1.08	0.9
80 lb bag	3.6	2.4	1.8	1.44	1.2
1 cubic yard	162	108	81	65	54

Coverage tips

Thin pours stretch further, but have limits. Bagged mix is made for pours 2 in or thicker.
Hold some back. Uneven ground and spillage use more than the math says.
Metric bags vary. A 20 kg bag yields about 9 to 10 L depending on the product; pick the product that matches your bag.

Questions people ask

How much area does an 80-lb bag of concrete cover?

At 4 in thick, one 80-lb bag (0.60 ft³) covers 1.8 ft². At 2 in it covers 3.6 ft².

How many square feet does a yard of concrete cover?

At 4 in thick, one cubic yard covers 81 ft². At 6 in it covers 54 ft².

How many bags for 100 square feet?

At 4 in thick, 100 ft² is 33.33 ft³. That's 56 80-lb bags exactly, or 62 with 10% extra.

How much does a cubic meter cover?

One cubic meter covers 10 m² at 100 mm thick, or about 6.7 m² at 150 mm.

Sources

QUIKRETE Concrete Mix No. 1101 product data sheet, retrieved October 2, 2026
SAKRETE High-Strength Concrete Mix technical data sheet, retrieved October 2, 2026
Easy Mix Super Strength Concrete technical data sheet, retrieved October 2, 2026
Australian Builders High Strength Concrete Mix product data sheet (ICL), stated as about 100 bags per cubic metre, retrieved October 2, 2026

Last updated October 2, 2026. Read how we calculate, including formulas, waste defaults and rounding.