Mesh versus rebar grid
Rolled wire mesh comes in sheets or rolls laid flat on chairs; a rebar grid is bars tied at each intersection. Both are measured the same way — bars in one direction plus bars in the other, at your spacing. The calculator returns total linear footage so you can buy either 10-foot rebar lengths or mesh rolls by coverage.
Support it or waste it
Unsupported mesh ends up at the bottom of the slab doing almost nothing. Use mesh chairs every couple of feet, pull the sheet flat mid-pour with a hook, and overlap adjacent sheets one full mesh square. The 10% extra in the calculation covers overlaps and edge trimming.
Sources and standards
Where these figures come from
Every formula on this page is implemented from the published reference material below. Where a value depends on a regional code, the calculator lets you override it rather than assuming one jurisdiction.
- ASTM International — C94 for ready-mixed concrete, C150 for cement and C143 for slump testing.
- American Concrete Institute — ACI 318 code requirements and ACI 302 slab construction guidance.
- Portland Cement Association — mix design, yield and curing data published by the US cement industry.
Figures, formulas and reference tables last verified: 19 September 2026.