Concrete and Screed Calculator
Enter the area and the thickness of a slab, a base or a floor screed. You get the volume in cubic metres and litres, and the number of bags if you use bagged mix.
The thickness is an example. Use the one your perit, contractor or product sheet gives.
Screed you need
1.1 m³
- Area
- 20 m²
- Litres
- 1,100
- Bags
- Enter the bag yield
For large volumes, ask your contractor about ready-mixed concrete delivered by truck.
How it works
- 1Volume = length × width × thickness (in metres), plus the allowance.
- 21 m³ = 1,000 litres.
- 3Bags = litres needed ÷ the litres one bag makes (printed on the bag as the yield), rounded up.
- 4Uneven bases, falls for drainage and spillage all use more than the flat sum, so keep an allowance and ask your contractor how thick the screed must be.
Questions
How thick should a floor screed be?
It depends on the screed type, whether there is underfloor heating or insulation under it, and whether it is bonded to the slab. Your perit, contractor or the product sheet will give the minimum thickness. Use that number here, and measure the deepest points too.
Bags or ready-mixed concrete?
Bags suit small jobs you can mix by hand or in a small mixer. For larger volumes, ready-mixed concrete delivered by truck is usually easier and more even. Ask your contractor which suits the volume and the access to your site.
Where do I find the yield of a bag?
The bag or the product sheet says how many litres, or square metres at a given thickness, one bag makes when mixed as instructed. Use that number, because it varies by product.
Bigger job? Plan it step by step
Describe your build or renovation and get the steps in order, a checklist for each one and a rough timeline.
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