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Rebar Calculator

Calculate rebar quantity, spacing, weight, and cost for slabs, footings, walls, and columns. Supports grid layouts, lap splices, and multi-zone projects.

Concrete Slab / Grid

Bidirectional rebar grid for slabs, pads, and flatwork

Pricing

Common Project Presets

Rebar Requirements

Grid Layout Preview

Schematic view of rebar grid pattern

Spacing Comparison

How bar count changes with different spacings

SpacingBars (L)Bars (W)Total BarsLinear FtWeight (lbs)Est. Cost

Placement Notes & Tips

Rebar Summary

Enter dimensions and click
Calculate

Rebar Size Reference

#3 (3/8")0.376 lb/ft
#4 (1/2")0.668 lb/ft
#5 (5/8")1.043 lb/ft
#6 (3/4")1.502 lb/ft
#7 (7/8")2.044 lb/ft
#8 (1")2.670 lb/ft

Typical Spacing Guide

Driveway slab#4 @ 12" OC
Patio / walkway#3 @ 18" OC
House slab#4 @ 12" OC
Garage floor#4 @ 16" OC
Foundation footing#5 @ 2 rows
Retaining wall#5 @ 12" OC

Lap Splice Guide

#315" min
#420" min
#525" min
#630" min
#735" min
#840" min

Class B splice (most common). Verify with engineer.