SlabYd · materials
SlabYd slab volume yd3
Know how many cubic yards of concrete to order for a rectangular slab pour
Result
volume_ft3=L·W·(thickness_in/12); volume_yd3=volume_ft3/27; bags=ceil(volume_ft3/bag_yield_ft3) with user-supplied bag yield
How to use this estimate
Estimate concrete slab volume in cubic feet and cubic yards from length, width, and thickness. How it works: volume_ft3=L·W·(thickness_in/12); volume_yd3=volume_ft3/27; bags=ceil(volume_ft3/bag_yield_ft3) with user-supplied bag yield. Out of scope: irregular pads; waste factor beyond ceil bags; rebar scheduling; psi mix design. This is an approximate screening estimate, not a substitute for manufacturer charts or a full engineering design. Does not certify code compliance; confirm manufacturer data where it applies.
Sources, methodology, and assumptions
Methodology
volume_ft3=L·W·(thickness_in/12); volume_yd3=volume_ft3/27; bags=ceil(volume_ft3/bag_yield_ft3) with user-supplied bag yield
Assumptions
Flat rectangular slab; Bag yield from product label. This is an approximate screening estimate, not a substitute for manufacturer charts or a full engineering design.
Out of scope
irregular pads; waste factor beyond ceil bags; rebar scheduling; psi mix design
Sources
Last technically reviewed: 2026-09-11