How to Calculate Concrete Volume in Cubic Meters
The Concrete Calculator (Cubic Meters) 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.
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.
Key Features of the Concrete Calculator (Cubic Meters)
Metric-first dimension inputs
Length, width, and depth fields default to metres (m), with cm and mm also available — no unit-conversion arithmetic required.
Direct m³ volume entry
Switch to Volume mode and type the cubic metres directly — or enter ft³ / yd³ to get m³ as the primary output.
Three project presets (metric defaults)
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.
Three concrete-type options
Normal weight (2,400 kg/m³), lightweight ACI 213R (1,762 kg/m³), and bag-mix (2,130 kg/m³) — density constants sourced from a single shared table across this entire site.
Metric bag counts (20 / 25 / 40 kg)
Results show how many 20 kg, 25 kg, and 40 kg pre-mix bags you need, rounded up to whole bags — the standard metric bag sizes used in most non-US markets.
US lb bag counts in Advanced mode
Enable Advanced mode to also see 40 / 50 / 60 / 80 lb bag counts — useful when US products are available alongside metric bags on the same project.
Weight in kg, metric tons, lb, and short tons
All four weight units displayed simultaneously — kilograms and metric tons first, then pound and short-ton equivalents for cross-border coordination.
Volume in m³, ft³, and yd³ simultaneously
The results panel shows all three volume unit systems at once so you can read whichever the concrete supplier or structural drawings require.
Mixed-unit inputs supported
Each dimension field carries its own independent unit selector (m / cm / mm / ft / in). Enter length in metres and thickness in millimetres if that matches your drawings.
Print / PDF export
The Print / Save button opens a clean, print-optimised page listing all inputs, volume, weight, and bag counts. Use your browser's Print dialog to save as PDF.
Large-pour compliance flag
For pours exceeding 15 m³ (≈ 20 yd³) the calculator shows an ACI 302.1R note recommending a pre-pour mix-design review and independent QC testing.
Reciprocal cross-links
Results include direct links to the Concrete Yards Calculator (yd³ / lb-bag focus) and the Concrete Weight Calculator (weight-from-volume focus) so you can navigate without back-tracking.
How to Use the Concrete Calculator (Cubic Meters)
- 1Select Quick for a straightforward m³ result, or Advanced to also reveal US lb bag counts and the density / volume-conversion reference cards.
- 2Choose a project type preset — Slab / Floor, Footing / Wall, or Column / Pier — to pre-load sensible metric dimensions. Override any field if your actual dimensions differ.
- 3Select your input mode: Dimensions (L × W × D) to enter physical measurements, or Volume to type a known m³, ft³, or yd³ value directly.
- 4Enter your dimensions in the metric units that match your drawings: metres (m), centimetres (cm), or millimetres (mm). You can also select ft or in per field if your drawings mix systems.
- 5Select the concrete type: Normal Weight (2,400 kg/m³ per ACI 318), Lightweight (1,762 kg/m³ per ACI 213R), or Bag Mix (2,130 kg/m³).
- 6Press Calculate. The results panel updates immediately with volume in m³, ft³, and yd³; weight in kg, metric tons, lb, and short tons; and metric bag counts.
- 7Read the Metric Bag Counts section for how many 20 kg, 25 kg, and 40 kg bags you need, each rounded up to the next whole bag.
- 8Check the Weight section for kilograms and metric tons — useful for structural dead-load checks, truck weight limits, and concrete pump capacity calculations.
- 9Enable Advanced mode to view the equivalent US lb bag counts (40 / 50 / 60 / 80 lb) and the density and volume-conversion reference cards.
- 10Click Print / Save after calculating to export a clean PDF-ready summary of all inputs, volumes, weights, and bag counts for your project records.
Formulas Used in the Calculator
- 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.
Metric Bag Count & Weight Reference Table
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.
| Volume | Weight (kg) | Weight (t) | 20 kg bags | 25 kg bags | 40 kg bags | Equiv. yd³ |
|---|---|---|---|---|---|---|
| 0.5 m³ | 1,200 kg | 1.2 t | 54 | 43 | 27 | 0.65 yd³ |
| 1.0 m³ | 2,400 kg | 2.4 t | 107 | 86 | 53 | 1.31 yd³ |
| 2.0 m³ | 4,800 kg | 4.8 t | 213 | 171 | 106 | 2.62 yd³ |
| 3.0 m³ | 7,200 kg | 7.2 t | 320 | 257 | 158 | 3.92 yd³ |
| 5.0 m³ | 12,000 kg | 12.0 t | 532 | 428 | 264 | 6.54 yd³ |
| 10.0 m³ | 24,000 kg | 24.0 t | 1,064 | 855 | 527 | 13.08 yd³ |
| 15.0 m³ | 36,000 kg | 36.0 t | 1,596 | 1,282 | 790 | 19.62 yd³ |
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.
Standards & References
Source for the normal-weight concrete density constant of 2,400 kg/m³ (150 pcf) used as the primary density in this calculator.
Source for the lightweight concrete density of 1,762 kg/m³ (110 pcf) used in the Lightweight preset.
Governs how fresh concrete density is measured in the field. The density values in this calculator are consistent with ASTM C138 test methodology for normal-weight concrete.
Basis for the large-pour compliance flag shown when the calculated volume exceeds 15 m³ (≈ 20 yd³), recommending a pre-pour mix-design review and independent QC testing.
Standards cited for reference. Always consult a licensed structural or civil engineer for project-specific design requirements.
Frequently Asked Questions
What is a concrete cubic meter calculator?
A concrete cubic meter calculator converts project dimensions — entered in metres, centimetres, or millimetres — into concrete volume in m³ and then into weight in kilograms and metric bag counts. This calculator uses ACI 318 density constants (2,400 kg/m³ for normal-weight concrete) and returns all outputs in metric units first, with imperial equivalents alongside.
How does a concrete cubic meter calculator work?
It multiplies length × width × depth to get volume in m³, then multiplies by the concrete density (e.g. 2,400 kg/m³ for normal weight) to get mass in kg. Bag counts are derived by dividing the m³ volume by the yield per bag: 0.0094 m³ per 20 kg bag, 0.0117 m³ per 25 kg bag, and 0.019 m³ per 40 kg bag. All values are rounded up to the next whole bag.
How much does 1 cubic meter of concrete weigh in kg?
One cubic metre of normal-weight concrete weighs 2,400 kilograms (2.4 metric tons) per ACI 318. Lightweight concrete (ACI 213R) is approximately 1,762 kg/m³. Pre-mix bag-mix concrete is approximately 2,130 kg/m³. These density values are sourced from the site's shared, spec-locked density table used by every calculator on this site.
How many 20 kg bags of concrete fill 1 cubic meter?
A 20 kg bag yields approximately 0.0094 m³ of concrete. To fill 1 m³ you need 1 ÷ 0.0094 = 106.4, rounded up to 107 bags. This calculator shows the exact count for your volume automatically.
How many 25 kg bags fill 1 m³ of concrete?
A 25 kg bag yields approximately 0.0117 m³ of concrete. One cubic metre requires 1 ÷ 0.0117 = 85.5, rounded up to 86 bags of 25 kg concrete.
How many 40 kg bags fill 1 m³ of concrete?
A 40 kg bag yields approximately 0.019 m³ of concrete. One cubic metre therefore requires 1 ÷ 0.019 = 52.6, rounded up to 53 bags. The 40 kg bag is the most common large pre-mix size in metric markets and gives the most economical bag count.
How do I convert cubic meters to cubic yards?
Multiply m³ by 1.30795 to get cubic yards. For example, 5 m³ = 5 × 1.30795 = 6.54 yd³. This calculator displays the yd³ equivalent automatically in the Volume section of the results panel.
How do I convert cubic meters to cubic feet?
Multiply m³ by 35.3147 to get cubic feet. For example, 1 m³ = 35.3147 ft³. The calculator shows ft³ alongside m³ and yd³ in all results so you can cross-check against plan-set notes or US product data sheets.
What is the density of concrete in kg/m³?
Normal-weight concrete: 2,400 kg/m³ (ACI 318). Lightweight concrete: approximately 1,762 kg/m³ (ACI 213R). Bag-mix pre-blended concrete: approximately 2,130 kg/m³ (derived from the standard 40 kg bag yield of 0.019 m³). The calculator's Concrete Type buttons switch between these constants automatically.
What dimensions give me 1 cubic meter of concrete?
Any L × W × D combination that multiplies to 1.0 m³. Common examples: a 2 m × 2 m slab 0.25 m thick (2 × 2 × 0.25 = 1.0 m³); a 10 m strip footing 0.5 m wide × 0.2 m deep (10 × 0.5 × 0.2 = 1.0 m³); or a 100 mm × 100 mm column 100 m tall. Use the Dimensions input mode and adjust each field until the result reads 1.000 m³.
How do I calculate concrete for a metric slab?
Select the Slab / Floor preset, then adjust the length, width, and thickness to your actual dimensions in metres or centimetres. A typical residential slab is 150 mm thick (0.15 m). For a 10 m × 8 m slab at 150 mm: 10 × 8 × 0.15 = 12 m³. At 2,400 kg/m³, that is 28,800 kg (28.8 t), requiring 636 × 20 kg bags or 228 × 40 kg bags.
What is the difference between this calculator and the Concrete Yards Calculator?
This calculator is metric-first: dimension inputs default to metres (m/cm/mm), the primary volume output is m³, and bag counts feature 20/25/40 kg metric bags. The Concrete Yards Calculator is yd³-first: dimension inputs use feet, the primary output is cubic yards, and bag counts feature US lb bags. Both calculators use the same shared calculation engine so the math is identical — only the default units and primary outputs differ.
What is the difference between this calculator and the Concrete Weight Calculator?
The Concrete Weight Calculator is weight-out focused — its hero output is total weight in pounds and tons, making it suited for dead-load checks, haul-away estimates, and structural reviews. This calculator is volume-out focused — its hero output is m³, making it suited for ordering concrete and planning pours. Both calculators share the same engine and density table; choose this one when you need metric volume and bag counts, and the weight calculator when weight is the primary deliverable.
Is the calculator free?
Yes — completely free with no sign-up, no account, and no download required. All calculations run locally in your browser.
Can I print or save my estimate?
Yes. After pressing Calculate, click the Print / Save button to open a clean print-optimised page listing all inputs, volume in m³/ft³/yd³, weight in kg/t/lb/tons, and both metric and US bag counts. Select 'Save as PDF' in your browser's Print dialog to keep a digital copy for site records or client deliverables.
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