Concrete calculator — volume, ballast and cement

Enter the size of your slab, base or footing and pick a mix. The calculator gives the concrete volume in cubic metres and the ballast and cement bags to order.

Enter the slab or footing size (metres or mm) and we work out the concrete volume and the ballast, cement and water you'd need to mix it yourself.

Wastage

Concrete needed

2520.00 m³(incl. 5% waste — 2400.00 m³ net)

Or ≈ 2520.0 m³ of ready-mix delivered

  • Ballast (all-in)5670 bulk bags
  • Portland cement30240 × 25kg bags
  • Water (approx.)415800 litres

Figures are indicative nominal mixes — confirm the spec with your engineer or supplier before ordering.

How it works

  1. 1Measure the area — length, width and depth. A shed base is usually 100mm deep; a driveway or garage base is often 150mm.
  2. 2Pick your mix. A general-purpose 1:2:4 mix suits paths and bases; a stronger mix suits driveways and footings.
  3. 3Read the volume in cubic metres. That's the figure a ready-mix supplier will ask for if you'd rather order it delivered.
  4. 4Or read the bag quantities. The calculator converts the volume into bulk bags of ballast and 25kg bags of cement for mixing on site.
  5. 5Allow a little extra. Uneven ground eats concrete — most people order around 10% over for a base dug by hand.

Now find the cheapest place to buy

Take your quantities across to Price Planter and compare them across UK builders' merchants — including whether splitting the order across two merchants works out cheaper.

Compare material prices

Volumes and bag quantities use typical trade conversion figures and are a guide only — confirm with your groundworker or ready-mix supplier before ordering.

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