Concrete Calculator
Enter dimensions for your concrete project, choose the shape, and instantly get the volume in cubic metres and cubic yards — plus estimated weight for ordering.
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Measurements convert when you switch units
Result
The formula
Slab volume is length × width × depth. Column volume is π × radius² × height. Wall volume is length × height × thickness. Results convert with 1 m³ ≈ 1.308 cubic yards. Concrete weight uses 2.4 tonnes/m³ (typical ready-mix).
Worked example
- Concrete slab 4 m × 3 m × 0.15 m → 1.8 m³
- Circular column r = 0.3 m, h = 3 m → π×0.09×3 ≈ 0.85 m³
- Wall 10 m × 2 m × 0.2 m → 4 m³ ≈ 5.23 cubic yards
Result: Concrete volume with automatic cubic metre/yard conversion and weight estimate
How concrete volume is calculated
Each shape applies standard geometric volume formulas, then converts between cubic metres and cubic yards. Weight estimates use typical concrete density.
Slabs, beams, and pads
A concrete slab is length × width × thickness (depth). For rectangular pads or footings, use the same formula. Make sure all dimensions are in the same unit — the calculator handles conversion between metric and imperial, but not mixed inputs.
Columns and circular footings
A round column uses πr² × height, where r is the radius. If you only know the diameter, divide by 2 first. Circular piers and sonotubes follow the same formula.
Walls and panels
A concrete wall is length × height × thickness. The thickness is the depth of concrete pour (usually 0.15–0.25 m or 6–10 inches for residential).
Units
Metric mode expects metres and reports cubic metres (m³) first, plus cubic yards. Imperial mode expects feet and reports cubic yards first, plus cubic metres. Always use consistent units for all dimensions.
Concrete density and weight
Standard ready-mix concrete weighs about 2.4 tonnes per cubic metre (150 lb/cu ft). Weight estimates help you plan delivery and placement. Reinforced concrete and specialty mixes may vary — consult your supplier for exact specifications.
What we do not model
No waste factor, slump loss, evaporation, or rebar volume. No custom concrete types (lightweight, fibre-reinforced, or self-consolidating). For complex shapes, break them into simple shapes and add the volumes.
Interesting facts
Ready-mix concrete standard weight
Typical 20–25 MPa concrete is 2.35–2.45 tonnes/m³. The calculator uses 2.4 t/m³; heavier mixes may exceed this. Check with your concrete supplier for your local product.
Cubic metres to cubic yards
1 m³ ≈ 1.30795 cubic yards (or 1 cubic yard ≈ 0.764555 m³).
Concrete sets in stages
Initial set occurs in 3–6 hours, final set in 24 hours; full strength develops over 28 days. Plan delivery, placement, and finishing accordingly.
Depth matters for slabs
Residential floors and walkways: 4 inches (0.1 m) minimum. Driveways: 4–6 inches (0.1–0.15 m). Heavy machinery pads: 6–8 inches (0.15–0.2 m) or more.
Add 5–10% waste factor
Spillage, uneven grades, trim loss, and rounding mean you should always order slightly more than the calculated volume.
Reinforcement volume is negligible
Rebar and wire mesh displace less than 1 % of concrete volume; no adjustment is needed for typical reinforcement.
Truck capacity affects pours
A ready-mix truck often carries about 7–10 cubic yards per load. Large pours may need multiple timed deliveries to avoid cold joints.
Subgrade prep changes real usage
Poorly compacted or uneven subgrade can increase actual concrete consumption beyond estimates, especially on wide slabs.
Cold and hot weather need different practice
Hot weather speeds set and water loss; cold weather slows strength gain. Placement and curing plans should match site temperature.
Frequently asked questions
For a 10 ft × 10 ft × 4 in slab: 10 × 10 × (4÷12) = 33.33 cubic feet ≈ 1.24 cubic yards. Switch to Imperial mode, enter length 10 ft, width 10 ft, depth 4 inches (or 0.333 ft), and calculate.
Volume = π × r² × h, where r is radius and h is height. For a column with diameter 0.6 m and height 3 m: π × 0.3² × 3 ≈ 0.849 m³.
Use length × height × thickness. For a 20 m wall, 2.5 m tall, 0.2 m thick: 20 × 2.5 × 0.2 = 10 m³ ≈ 13.08 cubic yards.
Concrete weight (volume × 2.4 t/m³) helps you plan delivery logistics and understand truck capacity. One cubic yard weighs roughly 1.5–1.6 tonnes.
A 5–10 % waste factor accounts for spillage, overfill, uneven ground, and trim waste. Always order a bit more than your calculated volume.
Yes — the volume formula works for any concrete shape. Specialty mixes (stained, stamped, polished) may have different densities; confirm with your supplier.
Break it into two rectangles, calculate the volume for each, then add them together.
Measure the depth at several points, average them, and use the average depth in the calculation. Or split the area into zones with different depths and add them up.
First calculate total volume in m³ (or yd³). Then divide by the bag yield listed on the product (for example, many 25 kg bags yield roughly 0.01–0.012 m³). Always include a waste margin.
Yes. Calculate full wall volume first, then subtract openings such as doors, windows, and service penetrations to avoid over-ordering.
If delays are long, separate placements may create a cold joint. Coordinate pour sequence with the supplier and site crew to maintain continuity.
Use finished in-place dimensions inside the forms. Measure actual form depth/width before pour day for the most accurate estimate.
References
- Concrete Specifications ACI standards for concrete mix design and practice.
- Unit Weight of Concrete Standard unit weight for ready-mix concrete approximately 2.4 t/m³.
- Metric and Imperial Conversion 1 m³ = 1.30795 cubic yards exactly.
- Building Code Requirements for Structural Concrete Standards for concrete strength, durability, and reinforcement in building construction.