Around 42 × 50 kg bags per m³ for ready-mix.

10% for hand pours/simple shapes. 15% for complex.

Volume estimate only. Confirm final quantity with your contractor.

No — rebar needs a separate schedule. This is volume only.

Yes — pick the imperial system and enter feet.

Concrete Calculator

Estimate concrete volume for your slab with a waste allowance and optional cost.

Practical calculatorGeneral editable assumptionsGlobal-readyInteractive chart

Last updated: 2026-05-31

This calculator uses generic assumptions. Use advanced mode to override them for a more accurate result.

Formula transparency

Source: default

V = L × W × D · Total = V × (1 + Waste%)

Bags per m³?: Around 42 × 50 kg bags per m³ for ready-mix.
Waste %?: 10% for hand pours/simple shapes. 15% for complex.
Accurate?: Volume estimate only. Confirm final quantity with your contractor.
Rebar?: No — rebar needs a separate schedule. This is volume only.
Imperial supported?: Yes — pick the imperial system and enter feet.

Results are estimates and not professional advice. Verify important decisions with a qualified professional.