How to calculate concrete in cubic meters

Volume (m³) = length × width × thickness, all in meters. Convert thickness first: 100 mm is 0.1 m and 15 cm is 0.15 m.

Example: a 6 m × 4 m slab, 100 mm thick, is 6 × 4 × 0.1 = 2.4 m³. With 10% for waste, order 2.64 m³.

Cubic meters for common slabs

Slab size (m)	100 mm thick	125 mm thick	150 mm thick
3 × 3	0.90 m³	1.12 m³	1.35 m³
4 × 3	1.20 m³	1.50 m³	1.80 m³
5 × 4	2.00 m³	2.50 m³	3.00 m³
6 × 4	2.40 m³	3.00 m³	3.60 m³
6 × 6	3.60 m³	4.50 m³	5.40 m³
10 × 5	5.00 m³	6.25 m³	7.50 m³

Converting to other units

Cubic meters	Cubic yards	Cubic feet	Weight
0.5 m³	0.65	17.7	1,200 kg
1 m³	1.31	35.3	2,400 kg
2 m³	2.62	70.6	4,800 kg
3 m³	3.92	105.9	7,200 kg
5 m³	6.54	176.6	12,000 kg
10 m³	13.08	353.1	24,000 kg

Weight uses 2,400 kg per cubic meter for normal-weight concrete.

Bags

The bag counts in the calculator are for US bags sold by the pound. Metric bag sizes and yields vary by country and brand, so check the yield printed on the bags you can buy and divide your volume by it.

Frequently asked questions

How do I calculate cubic meters of concrete?

Multiply length × width × thickness in meters. A 6 m × 4 m slab at 100 mm thick is 6 × 4 × 0.1 = 2.4 cubic meters.

How much does a cubic meter of concrete weigh?

About 2,400 kg, or roughly 5,300 lb.

How many cubic yards are in a cubic meter?

1.308 cubic yards. One cubic yard is 0.765 cubic meters.

How do I convert millimeters to meters?

Divide by 1,000. A 100 mm slab is 0.1 m thick.

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