Concrete Volume Calculator
About This Calculator
This concrete volume calculator helps you determine exactly how much concrete you need for your project. Whether you're pouring a slab, building footings, or constructing a foundation, getting the right volume is crucial for ordering materials and budgeting.
The calculator provides results in cubic metres, cubic yards, and cubic feet, plus estimates for cement bags (25kg and 50kg) and ready-mix concrete by the tonne.
How to Use
- Enter the length of your concrete pour in metres
- Enter the width in metres
- Enter the depth (either in metres or millimetres)
- Select the depth unit (metres or mm)
- Click Calculate to see your results
Example Calculations
Garden Slab
A patio slab measuring 5m × 4m at 150mm deep:
- Volume: 3.0 m³
- Ready-mix needed: ~7.2 tonnes
- Or approximately 21 × 50kg cement bags
Foundation Footings
A continuous footing 10m long, 400mm wide, 300mm deep:
- Volume: 1.2 m³
- Ready-mix needed: ~2.9 tonnes
Small Column
A column 300mm × 300mm, 2.4m high:
- Volume: 0.22 m³
- Ready-mix needed: ~0.5 tonnes
Important Notes
- Always order 5-10% extra concrete to account for wastage and variations
- Ready-mix concrete is typically ordered in multiples of 0.5m³
- Cement bag estimates assume a 1:2:4 mix ratio (cement:sand:aggregate)
- Actual coverage may vary based on mix design and placement conditions
Ready to Calculate?
Enter your measurements and get instant concrete volume calculations.
Open Calculator →Related Calculators
NAIBC / IRC codes
References & Sources
Standards Cited
- ACI 318 — Building Code Requirements for Structural Concrete
Defines concrete strength classes and specifying requirements for US construction - ASTM C94 — Standard Specification for Ready-Mixed Concrete
Standard for ready-mix concrete specification, including density and volume calculations
Formulas Used
- Concrete volume:
volumeM3 = length x width x depth x (1 + wastage% / 100)
Source: Basic geometry — Wastage defaults to 0% for backward compatibility; industry standard is 5-10% - Unit conversion (m3 to yd3):
volumeYd3 = volumeM3 x 1.308
Source: Standard unit conversion - Unit conversion (m3 to ft3):
volumeFt3 = volumeM3 x 35.315
Source: Standard unit conversion - Cement bags estimate:
bags25kg = ceil(volumeM3 x 12); bags50kg = ceil(volumeM3 x 6)
Source: ACI 318 (1:2:4 mix ratio) — Based on ~300 kg cement per m3 for a typical 1:2:4 mix - Ready-mix weight:
readyMixTons = volumeM3 x 2.4
Source: ASTM C94 — Ready-mix concrete density approximately 2400 kg/m3
Key Assumptions
- Ready-mix concrete density: 2400 kg/m3 — ASTM C94
- Cement bag estimate based on typical 1:2:4 mix ratio (~300 kg cement per m3 = 12 x 25kg bags) — ACI 318
- Wastage allowance defaults to 0% but 5-10% is recommended for site-mixed or ready-mix concrete — Industry standard practice