Rebar Calculator for Slab — Concrete-Depot.com

Measurement inputs

Live calculation updates as you type.

Slab rebar grid

Project name This name is used in the saved report.

Unit system Changing this keeps the same measurements.

Bar size Weight is estimated from common US rebar weights.

Slab length

Slab width

Rebar spacing

Edge cover

Stock bar length

Lap overlap

Waste / extra (%) Use 5% simple, 10% normal, or 15% complex.

Cost per linear ft Optional. Leave blank if cost is unknown.

Result dashboard

Total rebar length with waste –

Enter slab size and spacing to calculate rebar quantity.

10% waste

Bars running length –

Bars running width –

Stock bars to buy –

Estimated weight –

Cut length before waste –

Pieces before waste –

Actual spacing each way –

Estimated material cost –

Formula used

Rebar grid length = bars running length × clear length + bars running width × clear width + lap overlaps

Unit note: All measurements are converted to feet before calculation. This tool estimates material quantity only. Rebar design, spacing, cover, and splice length should be confirmed by your engineer, local code, or project drawings.

Calculation steps

Enter valid slab measurements to see the steps.