Length and Weight of Rebar in a Slab

The Length and Weight of Rebar in Concrete Slab calculator computes the total length and weight of rebar needed for one or more mats of rebar in a concrete slab.

INSTRUCTIONS: Choose units and enter the following:

  • (L) Length of the slab
  • (W) Width of the slab 
  • (oC) On-center spacing of the rebar spacing (defaults 18″)  
  • (i) Inset distance from the side of the slab to the rebar grid (default of 3″).
  • (M) Number of mats.  (default is one).
  • (RL) Length of the pre-cut rebar sticks being used to determine if lapping is required.
  • (rS) Rebar Size
  • (LF) Lapping Factor, the multiple of the diameter of the rebar to specify the lapping distance.  40 (default) and 60 are common.