Rebar Spacing Calculator
Calculate rebar spacing, quantity, and layout for concrete slabs, walls, and footings based on ACI code requirements.
Structure Parameters
Total Rebar Bars Needed
42 bars
21 x 21 per layer | 1 layer(s)
Spacing of 12" meets ACI 318 requirements (min: 1.33", max: 18")
Steel Area per Foot
0.200
in²/ft
Steel Ratio
0.417%
of concrete area
Total Rebar Length
840.0
ft (256.0 m)
Coverage Area
400.0
sq ft (37.2 m²)
Bar Layout
Long Direction
21 bars @ 12" o.c.
Short Direction
21 bars @ 12" o.c.
Total Weight
561.1 lbs
254.5 kg
ACI 318 Spacing Requirements
Minimum Spacing
- Clear spacing of at least 1 inch
- At least the bar diameter
- 1.33 times max aggregate size
Maximum Spacing
- Temperature/shrinkage: 18" or 5h
- Flexural reinforcement: 3h or 18"
- Slabs on ground: typically 12-18"