Concrete Weight Calculator
What a volume of concrete weighs, in kilograms and tonnes.
Your result
Enter a volume, or dimensions, above to see what it weighs.
This is useful for working out whether a load fits on a trailer, whether a slab can be lifted, or how much waste you are carting away. It is not a figure to design anything from. What a floor, a vehicle or a lifting point can safely carry needs an engineer.
How much does concrete weigh?
Weight = volume × density. Normal-weight concrete is around 2,400 kg per cubic metre — 2.4 tonnes.
Some figures that give a sense of scale:
- 1 m³ — about 2.4 tonnes. More than most car trailers are rated for.
- A 5 × 4 m slab at 100 mm (2 m³) — about 4.8 tonnes.
- A single 20 kg bag — 20 kg dry, and it yields only about 9 litres of concrete. You need roughly 110 of them per cubic metre, which is 2.2 tonnes of bags to shift by hand.
- A square metre of 100 mm slab — about 240 kg.
That last one is worth remembering. People underestimate concrete badly, because it is far denser than it looks.
Why density varies
2,400 kg/m³ is a typical figure for a standard mix, not a constant. Real density depends on the aggregate, the mix design, the water content and how much steel is in it. Heavier aggregates push it up; lightweight aggregates can bring it well below 2,000. Reinforced sections run a little higher because steel is roughly three times denser than concrete.
If you have been given a density for your specific mix, use the custom option — it will be more accurate than any default.
When this actually matters
- Trailer and ute loads. Half a cubic metre of concrete is over a tonne. Check your towing capacity before loading, not after.
- Carting away a broken slab. Demolition volume is easy to underestimate, and skip bins are priced and limited by weight.
- Lifting precast elements. Useful as a sanity check against the lifting gear — though the actual rigging calculation is not a job for a web page.
- Loading on an existing structure. A topping slab on a timber floor, or anything poured above ground, needs an engineer. This figure tells you the weight; it does not tell you whether the structure can take it.
Frequently asked questions
Is wet concrete heavier than cured concrete?
Slightly. Fresh concrete carries mix water, some of which is consumed in hydration and some of which evaporates over the following weeks. The difference is small — on the order of a few per cent — and well inside the variation between mixes. For practical purposes, use the same figure.
Does a 20 kg bag make 20 kg of concrete?
It makes slightly more, because you add water. But the number that matters when you are ordering is not weight, it is yield — a 20 kg bag typically makes about 9 litres of concrete. Use the bag calculator for counts.
Tonnes or tons?
Tonnes. A metric tonne is 1,000 kg. The imperial short ton is about 907 kg and the long ton about 1,016 kg, so quoting "tons" in Australia invites confusion. Everything here is metric.