Concrete & Masonry Calculators

Concrete work punishes bad estimates harder than any other trade a homeowner touches. Run short of studs and you drive back to the yard; run short mid-pour and you get a cold joint in your slab. That’s why every concrete-related tool on this site leans conservative and shows its allowances as separate lines you can judge for yourself.

The section opens with the rebar calculator, because reinforcement is the estimate people most often guess at: it lays out a proper grid from your slab dimensions, spacing and edge cover, counts bars in both directions, and adds lap-splice length where runs exceed stock bars. Tools for slab volume, bag counts, sonotubes, post holes, steps, mortar and block walls are on the roadmap for this category; until they land, the rebar calculator below is the one that’s live.

A note on buying: bagged concrete yields are small (an 80 lb bag is only 0.60 cubic feet), so slab jobs escalate from “a few bags” to “order ready-mix” faster than most people expect. When an estimate here crosses about a cubic yard, price a truck before you price a pallet of bags — your back and your slab will both thank you.