What is a concrete mix ratio?
A mix ratio defines the proportion of cement, sand, aggregate, and water required per cubic metre of concrete for a given grade such as M20.
Concrete Mix Ratio Calculator
Calculate cement, sand, aggregate, and water quantities for a concrete mix ratio by volume and grade.
Concrete Mix Ratio Calculator Formula
- Concrete Volume
Length × Width × Thickness (converted to m³) - Wastage Allowance
Volume × (1 + Wastage ÷ 100) - Mix Materials
Adjusted volume × grade ratios per m³ - Cement Bags
Cement (kg) ÷ 50 kg bag weight, rounded up
Assumptions
- Mix ratios follow standard nominal proportions for each selected concrete grade.
- Cement bags are assumed to be 50 kg unless configured otherwise.
- Wastage is applied to total concrete volume before material estimation.
Frequently Asked Questions
How much wastage should I add?
Most site pours use 5–10% wastage depending on formwork complexity and spillage.
Can I use this for a slab pour?
Yes. Enter slab length, width, and thickness. For slab-specific planning, also see the Slab Concrete Calculator.