Concrete mix calculator

Enter the dimensions of your structure: the calculator gives the concrete volume, then the amounts of cement (in kg and in 35 kg bags), sand, gravel and water for the mix you choose.

Length (m)

Width (m)

Thickness (cm)

Concrete mix Add a 10% margin (waste, uneven ground)

📦 Concrete volume
🧱 Cement
🛍️ Cement bags (35 kg)
🏖️ Sand
🪨 Gravel
💧 Water

Standard site mixes. Add the water gradually: overly wet concrete loses its strength. In hot weather, protect fresh concrete from drying out.

Standard mixes, per 1 m³ of concrete

Mix	Cement	Sand	Gravel	Water	Typical use
150 kg/m³	150 kg	0.55 m³	0.75 m³	≈ 85 L	Blinding concrete
250 kg/m³	250 kg	0.50 m³	0.75 m³	≈ 125 L	Light foundations
300 kg/m³	300 kg	0.50 m³	0.70 m³	≈ 150 L	Slabs, terraces
350 kg/m³	350 kg	0.45 m³	0.70 m³	≈ 175 L	Structural reinforced concrete

Remember the simple rule: for standard 350 kg/m³ concrete you need about 10 bags of 35 kg per m³. The mix is not everything: correct reinforcement and careful curing matter just as much for the strength of the structure.