Rebar Calculator
Calculate rebar quantity, spacing, and total length needed for concrete slabs, footings, and walls.
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How to Calculate Rebar for a Slab
Count bars in each direction: divide slab dimension by spacing and add 1. Multiply bars by length to get total linear feet. Add 10% for overlap at splices.
Frequently Asked Questions
What size rebar do I need?
#3 (3/8") for patios and walkways. #4 (1/2") for driveways and residential footings. #5 (5/8") for structural slabs and retaining walls.
What is standard rebar spacing?
12 inches on center for driveways, 18 inches for patios, and 24 inches for light-duty slabs.