A slab rebar takeoff should count bars in both directions from the actual grid spacing and concrete cover. Multiply bar count by run length, then add specified laps and development details before converting total footage to stock bar quantities.
Count bars in each slab direction from the specified spacing and usable dimension inside required concrete cover, multiply by run length, then add drawing-specified laps, hooks, dowels, and extras before stock-bar rounding.
Published: September 22, 2026
Last reviewed: September 22, 2026
Published by BuildYard. The guide reflects BuildYard's calculation methodology and editorial standards and does not replace project-specific professional advice.
Use the structural drawing for bar size, spacing, layers, and direction.
A quantity guide does not determine reinforcement design.
Bar runs normally stop inside the concrete edge by the required cover.
Use project details and applicable code rather than full slab dimensions by default.
For each direction, divide the usable perpendicular dimension by spacing and determine the required whole number of bars.
Check the end spaces rather than relying only on rounded division.
Splices, hooks, dowels, openings, thickened edges, and extra bars can materially change footage.
Use the structural schedule for required lap or development length.
Sum linear footage by bar size, plan cuts from available stock lengths, and round to whole bars.
Keep chairs, tie wire, couplers, and supports as separate takeoff items.
Concrete Calculator estimates ready-mix concrete, bag mix, weight, and truck loads for general slabs, pads, walls, and rectangular pours.
Open calculator →FoundationsFoundation Calculator estimates concrete for foundation wall or footing runs for early continuous-foundation material planning.
Open calculator →BuildYard quantity illustration only; structural drawings must specify bar size, spacing, cover, layers, and splice requirements.
| Direction | Planning result |
|---|---|
| Bars running 16 ft | Count across 12 ft at specified spacing |
| Bars running 12 ft | Count across 16 ft at specified spacing |
| Base footage | Sum bar counts × usable run lengths |
| Final footage | Add specified laps/details |
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Read guide →Current manufacturer data, supplier specifications, drawings, field measurements, applicable codes, permit requirements, and qualified professional guidance can take priority over a general-purpose planning estimate.