How to use it
- Choose the Element Type: Slab, Footing or Column. The form shows the dimensions for that element only.
- Enter the dimensions in metres. For a slab that is Length, Width and Thickness; for a footing, Footing Length, Footing Width and Footing Depth; for a column, Column Diameter and Column Height.
- Set Wastage (%) for spillage, uneven sub-base and over-excavation. The default is 5%.
- Read Base Volume (the exact geometric volume) and Total Volume (with wastage). Order the Total Volume, and repeat per element if the job has several.
The formula
Slab and footing volume = length × width × thickness (or depth). Round column volume = π × (diameter ÷ 2)² × height. Total volume = base volume × (1 + wastage ÷ 100). All dimensions are in metres, so the result is in cubic metres (m³).
What changes the result
Thickness is the biggest lever on a slab: every extra 50 mm on a large floor adds a lot of concrete. Wastage also matters; an uneven blinding layer, formwork leakage or pump line priming all use concrete you will not see in the final element. Rebar and openings are normally ignored, so deduct large voids such as shafts yourself.
Ordering on UAE sites
Ready-mix is ordered and charged by the cubic metre and delivered in transit mixers, so round the Total Volume up to a practical load rather than ordering to the decimal. For elevated slabs and tall columns a concrete pump is usually needed, and the supplier will ask for the grade, slump and pour time. In summer, many Gulf sites schedule large pours for the early morning or night to keep the mix cooler.
Worked examples
- A 6 m × 4 m slab, 150 mm thick, is 3.6 m³ of concrete; with 5% wastage, order 3.78 m³.
- A 12 m × 10 m ground-floor slab at 200 mm needs 25.2 m³ with 5% wastage - enough to plan a pump and several truckloads.
- One 1.8 m × 1.2 m isolated footing, 500 mm deep, takes 1.08 m³, or 1.134 m³ with 5% wastage.
- A 400 mm round column, 3 m high, holds 0.377 m³; allow 0.396 m³ with wastage.
Slab volume by thickness (6 m × 4 m slab)
Printable chart| Thickness (m) | Base volume (m³) | With 5% wastage (m³) |
|---|---|---|
| 0.1 | 2.4 m³ | 2.52 m³ |
| 0.125 | 3 m³ | 3.15 m³ |
| 0.15 | 3.6 m³ | 3.78 m³ |
| 0.2 | 4.8 m³ | 5.04 m³ |
| 0.25 | 6 m³ | 6.3 m³ |
| 0.3 | 7.2 m³ | 7.56 m³ |
| 0.4 | 9.6 m³ | 10.08 m³ |
A 6 m × 4 m slab with 5% wastage. For another size, enter your own length and width above.
Frequently asked questions
How do I calculate concrete volume for a slab?
Multiply length × width × thickness, all in metres, to get cubic metres. Add a wastage allowance, usually 5%, and order that total.
How much concrete do I need for a footing?
Multiply footing length × width × depth for each footing, then add the footings together. Use the Footing option above for one footing and repeat for the others.
How do I calculate the concrete for a round column?
Use π × (diameter ÷ 2)² × height. Choose Column above and enter the diameter and height in metres.
How much wastage should I add to concrete?
About 5% is a common allowance, more for rough excavations or long pump lines. Your site engineer or supplier can advise on the right figure for the job.
Does the calculator deduct rebar?
No. Reinforcement takes up a small share of the volume and is normally ignored when ordering concrete.
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