Rebar Calculator — Linear Feet & Weight for a Slab

How the rebar calculator works

Rebar is placed in a grid. Bars run each direction at the chosen spacing. Total linear feet = (bars long × slab length) + (bars short × slab width). A standard rebar stick is 20 ft.

#4 bar weighs 0.668 lb/ft. Divide linear feet by 20 to get sticks to order.

Frequently asked questions

What spacing should rebar be in a slab?

16 in OC is typical for residential slabs. 12 in OC for heavier loads (driveways with trucks) and 24 in OC for light patios.

What size rebar for a driveway?

#4 (1/2 in) rebar in a 12–16 in grid is standard for residential driveways 4–6 in thick.

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