Calculate how many concrete bags or cubic yards a project needs
Estimate cement, sand, and aggregate from custom mix ratios Covers slabs, posts, columns,...
This calculator computes the cement weight needed and converts it to a bag count assuming standard 50 kg bags — the common size in most of the world. Add 5-10% for waste, which the calculator already factors in via the waste factor field. If you buy US 40, 60, or 80 lb bags, convert the reported kilogram figure yourself (1 kg ≈ 2.2 lb) to get your bag count.
Concrete projects often require more material than exact math suggests due to spillage, uneven ground, or form spreading. Adding 5-10% waste is standard practice. For irregular shapes, use 10-15%.
Volume = π × radius² × depth. For a 10-inch diameter hole (5-inch radius) that is 3 feet deep: π × 0.417² × 3 = 1.64 cubic feet. Select the Circular Column shape in this calculator and enter diameter and height for an instant result.
A common standard mix for residential slabs is 1 part cement : 2 parts sand : 4 parts aggregate (1:2:4, roughly M15, ~15 MPa / ~2,175 psi). For driveways or high-traffic areas, use a stronger 1:1.5:3 mix (roughly M20, ~20 MPa / ~2,900 psi). Select a standard mix in this calculator, or switch to Mix Design mode to enter your own custom ratio.
Yes. In guest mode you can export your calculations to JSON. Signing in adds PDF and CSV export. Click the export button to download your results — useful for record-keeping, sharing, or importing into other tools.
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Yes. The Concrete Volume / Material Estimator is free to use with no sign-up required. A free account adds more calculation history, multiple workspaces, and access to your saved data from any device.
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Concrete Volume / Material Estimator
Calculate concrete volume and required quantities of cement, sand, aggregate, and water. Supports standard and custom mix ratios.