Concrete Volume Calculator
Calculate concrete volume for slabs, columns, footings, and cylindrical elements with wastage allowance and material estimates.
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About concrete quantity estimation
Accurate concrete quantity estimation is critical to avoid running short during a pour or over-ordering expensive material. The volume depends on the structural element shape: rectangular for slabs, columns, and footings; circular for cylindrical columns. An additional wastage allowance (typically 3-10%) covers spillage, formwork losses, and site measurements.
This calculator handles the four most common concrete pour shapes and outputs volume in cubic meters, cubic yards, approximate 40-kg bags, and weight (using 2400 kg/m³ for normal concrete). Real projects should verify quantities with the structural engineer and adjust wastage for site conditions.
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Common use cases
Ordering ready-mix concrete trucks sized in cubic meters or yards.
Estimating quantities for small pours using bagged cement.
Comparing bids from concrete suppliers based on total volume.
Checking structural drawings against architect specifications for volume consistency.
Frequently asked questions
What wastage should I use?
Typical values: 3-5% for large commercial pours with precise formwork, 5-10% for residential, 10-15% for small or irregular pours.
How many bags per cubic meter?
Approximately 30-33 bags of 40 kg cement per cubic meter of concrete (cement is only about 15% of total volume). This assumes 1:2:4 mix proportions.
Does concrete density depend on the mix?
Normal concrete is 2300-2500 kg/m³. Lightweight aggregate concrete: 1400-1900. Heavyweight (for radiation shielding): up to 4800 kg/m³. This tool assumes 2400.
Can I use this for reinforced concrete?
Yes. Steel rebar displaces a negligible volume (<1%) and does not significantly affect concrete quantity ordering.
Related tools
See our volume calculator for general earthwork and unit converter for cubic meter/yard conversions.