Home & DIY calculator
Convert slab dimensions into volume and premix bag quantity.
Part of: Concrete & masonry
Volume = length × width × depth. Purchase volume = volume × waste factor. Bags = round up(liters ÷ yield per bag).
A 3 m × 2 m × 10 cm slab is 0.6 m³. With 10% waste it becomes 0.66 m³, or 660 L. At 12 L per bag, buy 55 bags.
Common questions
A 10 x 10 ft slab 4 in thick is 33.3 cubic feet, or 1.23 cubic yards. Typical premix yields are about 0.60 cu ft for an 80 lb bag, 0.45 cu ft for a 60 lb bag and 0.30 cu ft for a 40 lb bag, so you need about 56 x 80 lb, 75 x 60 lb or 112 x 40 lb bags before waste (62, 82 or 123 with 10% waste). Check the yield on your bag and enter it in the calculator; at around a cubic yard or more, ready-mix is usually easier.
Subgrade variation, spillage, form dimensions, and ordering tolerances can leave a shortfall. Use a factor appropriate to your project and supplier.
That depends on project volume, access, labor, and local supply. This tool shows both volume and bag count so you can compare.
No. It estimates material volume only. Thickness, reinforcement, base preparation, drainage, and structural requirements need project-specific guidance.