Concrete Weight Calculator

Calculate the weight of a concrete pour from its volume or dimensions, by concrete type. Instant weight in kg/tonnes and cost estimate.

Concrete Weight Calculator: How Much Does Concrete Weigh?

Knowing how much a concrete pour weighs matters for more than curiosity. A structural engineer needs it to work out the dead load a slab, footing or column places on the ground and on whatever sits beneath it; a site manager needs it to check that a delivery truck, pump line or crane lift is not being asked to carry more than its rated capacity; and anyone building formwork needs it to be sure the props, ties and shuttering under a wet pour can actually take the load before it cures. Concrete is heavy — a cubic metre of ordinary concrete weighs roughly 2.3-2.4 tonnes, more than twice the weight of the same volume of water — so a volume figure alone, without converting it to weight, can seriously understate what you are actually moving, lifting or supporting.

This calculator converts a concrete volume into a weight in the unit you need — kilograms, tonnes, pounds or US tons — using the density of the concrete type you select, from lightweight asphalt concrete to dense reinforced concrete. Enter a volume directly if you already know it, or let the calculator work it out for you from the length, width and depth of a rectangular pour; either way, it multiplies that volume by the selected density and by how many identical pours you are making, then adds a material cost estimate on top.

How to Use the Concrete Weight Calculator

  1. Choose your input method: "Volume" if you already know the concrete volume, or "Dimensions" if you want the calculator to work it out from a rectangular pour.
  2. If using "Dimensions", enter the length, width and depth of the pour, choosing the unit for each (m, cm, ft or in).
  3. If using "Volume", enter the volume directly and choose its unit (m³, ft³, yd³, litres or US gallons).
  4. Set the quantity if you are pouring more than one identical slab, footing or element.
  5. Select the concrete type/density — asphalt concrete, gravel concrete, Portland-limestone cement concrete, Portland cement concrete or reinforced concrete — or enter a custom density.
  6. Choose your output unit for the weight (kg, tonnes, lb or US tons).
  7. Read off the total volume, the weight, and the estimated material cost.

The Math Behind the Calculation

The formula is simple: weight = volume x density. Density is the mass packed into a given volume of a specific material, and for concrete it depends mainly on the aggregate used and whether steel reinforcement is embedded in it — denser aggregate and added rebar both push the figure up.

If you enter dimensions rather than a direct volume, the calculator first works out the volume of the rectangular pour as length x width x depth (converting every dimension into the same unit first, since thickness is usually given in a much smaller unit than length and width). That per-pour volume is then multiplied by your quantity to get the total volume the weight calculation runs on.

Worked example: a 4 m x 3 m slab poured 100 mm (0.1 m) thick. Volume = 4 x 3 x 0.1 = 1.2 m³. Using a standard Portland cement concrete density of 2,300 kg/m³ (a widely used engineering reference figure), weight = 1.2 x 2,300 = 2,760 kg, or about 2.76 tonnes, for a single slab. Pouring three identical slabs would triple that to roughly 8.28 tonnes.

Reinforced concrete — ordinary concrete with embedded steel rebar or mesh — is denser than plain concrete, because steel (roughly 7,850 kg/m³) is nearly 3.5 times denser than the surrounding cement paste and aggregate. A commonly used reference figure for reinforced concrete is 2,500 kg/m³, around 8-9% heavier than the same volume of unreinforced Portland cement concrete. The same 1.2 m³ slab, if reinforced, would weigh 1.2 x 2,500 = 3,000 kg rather than 2,760 kg — a difference worth accounting for on anything structural.

Pro Tips and Common Mistakes

At around CA$170 per m³ of ready-mix concrete, the 1.2 m³ worked example on this page — a 4 m x 3 m slab poured 100 mm thick, weighing about 2,760 kg of Portland cement concrete — costs roughly CA$204 in material alone, before delivery, pumping and labour.

  • Always use the density that actually matches your mix, not a generic "concrete" assumption — the gap between a lightweight asphalt concrete (around 2,243 kg/m³) and reinforced concrete (around 2,500 kg/m³) is over 10%, enough to matter for a crane lift or a delivery weight limit.
  • Weight, unlike volume, does not change once concrete cures — a wet pour and the same concrete fully hardened weigh the same, since curing is a chemical reaction, not a loss of mass (some surface moisture does evaporate, but the effect on total weight is negligible for practical purposes).
  • Check vehicle and lift capacity before you order, not after — a standard ready-mix truck typically carries around 8-10 m³ per load, which at 2,300-2,500 kg/m³ is already 18-25 tonnes of concrete alone, before the vehicle's own weight.
  • For anything structural — a slab supporting a building, a suspended floor, a retaining element — the weight this calculator gives you is the dead load your foundation, formwork or supporting structure must be designed to carry; treat it as an input to a proper structural check, not the final word on adequacy.
  • If you are working from a delivery docket or a supplier's quote already denominated in weight (tonnes) rather than volume, you can run this calculator in reverse by dividing the quoted weight by the density to sanity-check the volume you are actually receiving.