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Slab Rebar Grid Calculator

Bars and total length for a rebar grid in a slab.

Compute the total number of rebar lengths and the total linear footage required for an orthogonal grid in a concrete slab from the slab dimensions, the bar spacing, and a 3-inch edge clearance.

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

ft
ft
in

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Bars_long = ceil(width / spacing). Bars_short = ceil(length / spacing). Total ft = bars_long · length + bars_short · width.

In depth

Compute the total number of rebar lengths and the total linear footage required for an orthogonal grid in a concrete slab from the slab dimensions, the bar spacing, and a 3-inch edge clearance.