Concrete volume calculator — cubic feet and cubic metres
Enter member dimensions and counts to get net concrete volume, the wastage allowance you choose, and the volume to order.
Member
Ordering
Wastage is site-specific. Order allowance, breakage and cutting loss differ by material, supplier and workmanship; enter your own figure.
Result — calculated from your inputs
Working
Continue to a full site assessment
A calculator answers one question. A DevPartner assessment carries planning capacity, programme, cost, revenue, deal structure and cash flow through one deterministic model and freezes a versioned decision report.
Nothing from this calculator maps into the assessment intake, so you will start from a blank site. No opportunity is created until you save one.
How this calculator works
volume = count × length × width × depth order = volume × (1 + wastage %) 1 cubic metre = 35.3147 cubic feet
- You enter
- A value you supply. Nothing is assumed for you.
- Calculated
- Arithmetic on your inputs, shown in the working.
- Assumption
- A factor or allowance you can change — mix ratios, wastage, dry-volume factors.
- Approximation
- Geometry or method that approximates reality; labelled wherever used.
- Verify locally
- Planning parameters, statutory rates and structural design must come from the authority or a qualified professional.
Order in cubic metres, measure in feet
Indian sites routinely measure members in feet and inches while ready-mix concrete is sold and pumped in cubic metres. The conversion is exact — one cubic metre is 35.3147 cubic feet — but doing it by memory on site is where short and over orders come from. This calculator shows both, always.
For ready-mix, order in whole loads where possible and check the supplier's minimum. A short pour that needs a second load hours later creates a cold joint, which is a structural problem rather than a logistics one.
What wastage should cover
Spillage during transfer, over-excavation in footings where the sides slump, formwork deflection that increases the effective slab thickness, pump line priming and the residue left in the drum. Three to five percent is common practice for controlled pours, and considerably more for footings on poor ground — but this is your judgement, not ours.
The calculator applies whatever figure you enter and shows the allowance separately, so the assumption is auditable rather than baked into the answer.
Worked example
A slab 10 m × 5 m × 0.15 m is 7.5 cubic metres, about 265 cubic feet. At 5% wastage the order quantity becomes 7.875 cubic metres. Add a second row for a 6 m × 0.23 m × 0.45 m beam and the two are totalled for a single pour.
Order in whole loads: the supplier's minimum load size usually determines the final number, not the arithmetic.
Mistakes in volume take-off
Mixing units within one row — a depth in millimetres against lengths in metres — which produces an answer a thousand times out.
Measuring the slab thickness as the finished floor level, including screed and finishes, rather than the structural thickness.
Forgetting to deduct large openings, shafts and cut-outs, or double-counting the beam volume already inside the slab depth.
Limits and assumptions
Wastage is entered by you. Site conditions, pump losses, formwork tolerance and over-excavation all affect it, and no single figure fits every pour.
This is a quantity take-off from dimensions you measured. It is not a structural design, a pour plan or a check on member size.
Frequently asked questions
- How do I calculate concrete volume for a slab?
- Multiply length by width by thickness in consistent units. A 30 ft by 20 ft slab at 6 inches (0.5 ft) thick is 300 cubic feet, or 8.495 cubic metres, before any wastage allowance.
- How many cubic feet are in a cubic metre of concrete?
- 35.3147 cubic feet. Multiply cubic metres by 35.3147 to get cubic feet, or divide cubic feet by 35.3147 to go the other way.
- Does this calculator tell me the concrete grade or slab thickness?
- No. Grade, thickness, reinforcement and member sizing are structural design decisions that must come from a qualified structural engineer for your specific loads, spans and soil. This calculator only computes volume from dimensions you supply.
- Should I order the net volume or the volume with wastage?
- Order the wastage-inclusive figure, then round up to the supplier's load size. Pump losses, formwork tolerance, over-excavation and spillage are real, and a short pour is far more expensive than a small surplus because a cold joint may have to be cut and treated.