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Calculator

Concrete Materials Calculator

Estimate cement, sand, and gravel for a rectangular slab or formwork.

Concrete Estimate

Slab or formwork size
Mix and cement bag
For example, 1 : 2 : 4 means 1 part cement, 2 parts sand, and 4 parts gravel.
Subtract embedded objects (optional)
Use this when rectangular objects inside the concrete reduce the required concrete volume.
Subtract rebars (optional)
Enter up to three rebar groups. Rebar volume uses circular volume with 3.14 for pi.

Rebar group 1

Rebar group 2

Rebar group 3

Show material loads (optional)
Enter the capacity of a truck, wheelbarrow, bucket, or other measuring container.
Assumptions
  • The calculator preserves the approved concrete ratio constants, unit conversions, densities, 52.4% dry-volume increase, and decimal formatting.
  • Cement, sand, and gravel densities are 1440, 1550, and 1350 kg per cubic meter respectively.
  • Embedded objects and rebars are optional deductions from the slab or formwork volume.
Disclaimer

This calculator provides an estimate for educational purposes only. It does not replace advice from construction specialists, contractors, or engineers.