Estimate concrete volume for a rectangular slab + approximate bag count (UK).
Length
Width
Units
Thickness / depth
Depth units
Waste / overage
Bag size
Concrete mix type
Enter values and press Calculate.
Assumptions: bag yield is based on density (kg/m³). Real yield varies by brand, water content, compaction, and whether you order ready-mix. For larger pours, treat this as a sense-check.