Concrete Cubic Meter Calculator

Calculating Concrete Volume in Metric Units

The concrete cubic meter calculator converts metric project dimensions — entered in metres, centimetres, or millimetres — into concrete volume in m³ and then into weight in kilograms and metric bag counts for 20 / 25 / 40 kg pre-mix bags. Whether you are ordering ready-mix concrete in a country that quotes by the cubic metre, estimating bag quantities from a metric materials list, or simply need your yd³ result expressed in SI units, this tool puts metric outputs first without forcing you to do any unit-conversion arithmetic. For the full set of cubic-yard, cubic-foot, and cubic-meter conversions, see our pillar guide to concrete volume conversions.

The calculator accepts three concrete types — normal weight (2,400 kg/m³ per ACI 318), lightweight ACI 213R concrete (1,762 kg/m³), and pre-mix bag concrete (2,130 kg/m³) — all drawn from the shared density table used by every calculator on this site so constants are never duplicated. Outputs include m³ volume, kg/t weight, metric bag counts, and US lb bag counts (in Advanced mode), plus equivalent ft³ and yd³ values for cross-border coordination. For weight in kilograms and tonnes, see our reference on how much concrete weighs; for a worked slab example, our guide on how to calculate concrete for a slab; and to estimate sacks, our guide to estimating bags of concrete.

Three project presets — Slab (6 × 6 × 0.15 m), Strip Footing (10 × 0.4 × 0.5 m), and Column (0.3 × 0.3 × 3.5 m) — load sensible starting values in seconds, and each dimension field carries its own independent unit selector (m / cm / mm / ft / in) so a drawing that mixes metres and millimetres still computes correctly. Quick mode keeps the results panel to volume, weight, and metric bag counts; Advanced mode adds US lb bag counts and the density / volume reference cards, plus an ACI 302.1R compliance note for pours over 15 m³. Every result links directly to the concrete yards calculator and concrete weight calculator, and a Print / Save button exports a clean PDF summary of every input and output.

Worked Example: A 10 m Strip Footing Pour

Consider a strip footing for a boundary wall — the calculator's own Strip Footing preset: 10 m long, 0.4 m wide, and 0.5 m deep. Volume is straightforward multiplication: 10 × 0.4 × 0.5 = 2.0 m³. Converted for cross-checking against imperial drawings: 2.0 × 35.3147 = 70.6 ft³, and 2.0 × 1.30795 = 2.62 yd³.

At the normal-weight density of 2,400 kg/m³, the footing weighs 2.0 × 2,400 = 4,800 kg, or 4.8 metric tons. If you are supplying the pour with bagged pre-mix instead of a ready-mix truck, the bag counts follow the same ceiling-rounded formula the calculator uses: 20 kg bags need ⌈2.0 ÷ 0.0094⌉ = 213 bags; 25 kg bags need ⌈2.0 ÷ 0.0117⌉ = 171 bags; and 40 kg bags need ⌈2.0 ÷ 0.019⌉ = 106 bags — the same figures listed against the 2.0 m³ row in the reference table below.

That 2.0 m³ is still the theoretical volume. Footings poured against trench walls lose some material to formwork gaps, over-excavation, and sub-grade irregularity, so many crews add a 5–10% ordering allowance on top of it — the same buffer concept ready-mix buyers apply on the imperial side of an order (see the concrete yards calculator for that equivalent). A 5–10% allowance raises this footing's practical order to roughly 2.1–2.2 m³ — round up to whatever load size your local plant offers.

The Cubic Meter Volume Formula

• 1) Rectangular volumeVolume (m³) = Length (m) × Width (m) × Depth (m)
  All dimension inputs are converted to metres before multiplication. For example, 600 cm is treated as 6 m, and 150 mm as 0.15 m.
• 2) Weight from volumeWeight (kg) = Volume (m³) × Density (kg/m³)
  Density constants: normal weight = 2,400 kg/m³ (ACI 318), lightweight = 1,762 kg/m³ (ACI 213R), bag mix = 2,130 kg/m³. Metric tons = kg ÷ 1,000.
• 3) Metric bag countsBags = ⌈ Volume (m³) ÷ Yield per bag (m³) ⌉
  Yields: 20 kg → 0.0094 m³, 25 kg → 0.0117 m³, 40 kg → 0.019 m³. All counts are rounded up (ceiling) to whole bags.
• 4) Volume conversionsft³ = m³ × 35.3147  |  yd³ = m³ × 1.30795
  Inverse: m³ = ft³ × 0.0283168  |  m³ = yd³ × 0.764555. All three volume units are shown simultaneously in the results panel.

Common Cubic Meter Volumes at a Glance

The table below shows pre-computed bag counts and weights for common pour volumes — useful as a quick sanity check against the calculator result. All bag counts are rounded up to the next whole bag; weight assumes normal-weight concrete at 2,400 kg/m³.

Bag counts rounded up. Weight assumes normal weight concrete (2,400 kg/m³). For lightweight or bag-mix concrete, use the calculator with the appropriate type selected.

Cubic Meter Ordering Mistakes That Leave You Short

• Using the wrong density constant. Normal weight (2,400 kg/m³), lightweight (1,762 kg/m³), and bag-mix (2,130 kg/m³) concrete give materially different weight and bag-count results for the identical m³ figure. Leaving the Concrete Type selector on the default when your project actually uses lightweight mix is the most common source of a mismatched order.
• Leaving one dimension field on the wrong unit. Each of length, width, and depth carries its own independent unit selector (m / cm / mm / ft / in). Entering depth in centimetres while length and width are still in metres silently shifts the volume by a factor of 100 rather than the intended small correction.
• Rounding bag counts down instead of up. The bag yields — 0.0094 m³ per 20 kg bag, 0.0117 m³ per 25 kg bag, 0.019 m³ per 40 kg bag — rarely divide evenly into a real volume. The calculator always rounds up (ceiling) to a whole bag; rounding to the nearest bag by hand instead leaves the pour short.
• Skipping the large-pour compliance check. Any pour exceeding 15 m³ (about 20 yd³) triggers an ACI 302.1R note recommending a pre-pour mix-design review and independent QC testing. On larger commercial or multi-slab jobs it's easy to sum several smaller sections and miss that the combined pour has crossed this threshold.
• Cross-referencing the wrong calculator's bag sizes. This tool's bag counts are 20 / 25 / 40 kg metric bags; the concrete yards calculator's are 40 / 60 / 80 lb US bags. Quoting one calculator's bag count against the other's product line produces an order that doesn't match what's on the supplier's shelf.

Specs & References

Standards cited for reference. Always consult a licensed structural or civil engineer for project-specific design requirements.