Rebar Calculator
Calculate rebar quantity, total length, and weight for a slab or footing grid
Results
Step-by-Step Calculation
How Rebar Quantity Is Calculated
Reinforcing bar (rebar) is laid out in a grid within concrete slabs and footings to add tensile strength. This calculator estimates the number of bars running in each direction, the total linear footage, and the total weight of steel you need to order.
Grid Formulas:
- Bars lengthwise: floor((Width x 12 - 2 x Clearance) / Spacing) + 1
- Bars widthwise: floor((Length x 12 - 2 x Clearance) / Spacing) + 1
- Total linear feet: (Bars lengthwise x Length) + (Bars widthwise x Width)
- Total weight: Total linear feet x Weight per foot
Common Bar Sizes (Imperial):
- #3 = 3/8 inch diameter, 0.376 lb/ft
- #4 = 1/2 inch diameter, 0.668 lb/ft
- #5 = 5/8 inch diameter, 1.043 lb/ft
Related Calculators
Note: This calculator provides estimates based on a simple two-way grid. Actual rebar requirements depend on structural engineering specifications, lap splices, bends, and local building codes. Always order extra to account for waste and overlaps, and consult a structural engineer for load-bearing applications.