Construction
How Much Concrete Do I Need?
Enter the slab dimensions and thickness. We return the volume, the number of bags, and the ready-mix order quantity.
- 01Measure
- 02Adjust
- 03Result
- 04Shop
01 — Measure
Tell us about the job
Paths 75–100 mm, driveways 125–150 mm
02 — Adjust
Material buffer
Excavations are never perfect. 5–10% covers uneven subgrade and spillage.
Before you start — measure this
- Slab length
- Slab width
- Slab thickness
03 — Result
1m³
Concrete required
- Nominal volume
- 0.9 m³
- Approx. weight
- 2,333 kg
04 — Shopping list
A 25 kg bag ≈ 0.0125 m³
78 × 0.01 m³
- Total purchased
- 1 m³
- Expected leftover
- 0 m³
Optional — planning estimate, not a live price.
Stored in this browser only. No account needed.
How we got this number
- Slab area
- 9 m²
- Thickness
- 10 cm
- Nominal volume
- 0.9 m³
- + 8% allowance
- 0.972 m³
Planning estimate: this calculation helps you estimate material quantities. Actual requirements vary with site conditions, product coverage, installation method and waste. Confirm with the manufacturer or a qualified professional when appropriate.
What to know about this material
- Bagged mix suits small pours; above about 1 m³ ready-mix is usually cheaper and faster.
- Ready-mix is normally ordered in 0.25 m³ steps — round up to the next step.
- Order all concrete for one slab in a single pour so it cures as one piece.
Frequently asked
- How many bags of concrete per cubic metre?
- About 80 bags of 25 kg mix, since each bag yields roughly 0.0125 m³.
- How thick should a slab be?
- 75–100 mm for footpaths and shed bases, 125–150 mm for driveways and anything carrying vehicles.
- Bagged or ready-mix?
- Under about 0.5 m³ bagged is practical. Over 1 m³, ready-mix delivery is normally cheaper and much less work.
Related calculators
What this calculator answers
The highest-intent, lowest-competition searches this page is built to answer outright — every one of them is a quantity question you can settle above without leaving the page.
- How many bags of concrete do i needKD 27
- How many bags of concrete for a 10x10 slabKD 11
- How much concrete for a fence postKD 27
- How much concrete do i need for a slabKD 0
Questions this page answers
This page is built around one job: work out volume for a slab, footing or post hole and bags to buy.
- How many bags of concrete for a 10x10 slab?
- How much concrete for a fence post hole?
- How many cubic yards in a 4 inch slab?
- How much concrete for footings?
Also known as: how much concrete do i need, concrete slab calculator, cubic yards of concrete, concrete bag calculator.