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Concrete Weight Calculator

Concrete weighs about 2.4 tonnes per cubic metre, and that number decides more than people expect — what your skip can legally take, whether a first-floor pour needs propping, and how many trips a trailer will make. Work out the weight from a volume or straight from slab dimensions.

Weight = Volume × Density
Concrete weight from volume and density
LengthWidthThickness
Slab dimensions

How much concrete weighs

Concrete type Per m³ Per yd³ Per ft³
Standard (normal weight) 2,400 kg (2.4 t) 4,050 lb (2.02 US tons) 150 lb
Lightweight 1,750 kg 2,950 lb 109 lb
High-density 2,500+ kg 4,200+ lb 156+ lb
Reinforced (design figure) 2,500 kg 4,215 lb 156 lb

Weight = Volume × Density — a 3 × 3 × 0.1 m slab is 0.9 m³ × 2,400 = 2,160 kg.

Engineers use 2,500 kg/m³ for reinforced concrete because the steel adds weight. Wet and cured concrete weigh almost the same; curing loses only a little water to evaporation.

Weights worth knowing

  • A 600 × 600 × 50 mm paving slab: about 43 kg — two-person lift
  • One square metre of 100 mm slab: 240 kg
  • A barrow of wet concrete (60 litres): about 145 kg, which is why they tip
  • Broken concrete, loose in a skip: 1,600 to 1,900 kg per m³

That last figure is the one that catches people out on demolition. Skip hire companies apply weight limits well below the visual capacity of the skip — many cap a builder’s skip at around a tonne of hardcore. Tell them it is concrete when you book, or you will be paying an overload charge.

Frequently asked questions

How much does a yard of concrete weigh?

About 4,050 lb — a little over two US tons for standard mix.

How much does a cubic metre weigh?

Around 2,400 kg (2.4 tonnes). Use 2,500 kg/m³ for reinforced concrete in design calculations.

How much does an 80 lb bag weigh once mixed?

Roughly 84 to 88 lb — the added water mostly stays in the mix. Yield is 0.60 ft³, giving mixed bagged concrete a density near 145 lb/ft³.

How much broken concrete can go in a skip?

Far less than the skip volume suggests. One cubic metre of broken slab is 1.6 to 1.9 tonnes, and most hire firms cap heavy waste well below the fill line. Book a dedicated hardcore skip.

Does concrete get lighter as it cures?

Marginally. Some mix water evaporates rather than reacting, but the change is small enough to ignore for practical purposes.

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