Bit & GrainBit & Grain

Rebar Spacing Calculator

Calculate total rebar linear footage, bar count by direction, and estimated weight for a concrete slab.

Weight: 0.668 lbs/ft

Slab area: 400 sq ft

Total Rebar Length840LF
Bars Running Lengthwise (20 ft)21bars
Bars Running Widthwise (20 ft)21bars
Estimated Weight561lbs
Placement note: Add 10 to 15% for laps and waste. Typical lap splice length is 25 bar diameters. Maintain 3 in of concrete cover minimum from slab edge to rebar per ACI 318.

For reference only. Verify with your local building code and a licensed professional before making decisions.

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