Rebar & Mesh Reinforcement Calculator
Calculate 20ft rebar sticks, grid intersections, tie wire pounds, and support chairs for concrete slab reinforcement.
Input Parameters
Enter dimensions and specifications to estimate materials.
20 ft Rebar Sticks Needed
Total Linear Length
911ft
Bar Size
#4 (1/2")
Grid Spacing
18in O.C.
Grid Intersections to Tie
294
Tie Wire
2lbs
Support Chairs
74chairs
Slab Area
600sq ft
Material estimates include recommended trade waste buffer. Always confirm dimensions on site prior to ordering.
How The Calculation Works
Formulas, material coverage assumptions, waste buffers, and rounding standards.
Bar counts are derived in each direction from the slab dimension less twice the edge clearance, divided by the grid spacing, plus one — the fencepost rule, which is where most manual estimates go wrong.
Lap splices are added wherever a run exceeds the 20 ft stock length. Standard practice is an overlap of 30 bar diameters, about 15" for #4 bar, and that overlap is real steel you have to buy.
Tie wire and support chairs are estimated from the number of grid intersections and a chair roughly every 3 ft, which keeps the mat at mid-depth where it does structural work.
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Frequently Asked Questions
Practical installation guidance and purchasing tips for rebar & mesh reinforcement calculator.