SlabCalc

About SlabCalc

SlabCalc is a concrete calculator for homeowners, DIY builders and contractors who need to know how much concrete a project requires before ordering. Users pick a shape such as a slab, cylinder, curb or stairs, enter dimensions in imperial or metric units, and choose a waste factor of 5, 10 or 15 percent. The results show cubic yards, bag counts for 40, 50, 60 and 80 pound mixes, total volume and estimated weight.

The tool is free and needs no signup. It covers nine shape types, including footings, sonotubes, walls and steps, and the site adds pre-configured calculators for specific jobs like patios, driveways and garage floors. Reference pages explain the volume formula and give yardage charts for common slab sizes.

What sets it apart is the focus on ordering decisions rather than just volume: it recommends bagged mix for small pours under a cubic yard and ready-mix delivery above that, and it explains why a waste margin matters on a continuous pour.