Calculated result
353ft
Rebar to order
Formula
CONC-REBAR-0018 bars
Long bars
14 bars
Cross bars
320.7 ft
Net linear quantity
Concrete calculator
Slab rebar calculator
Preliminary slab rebar count, linear footage and bar-weight planning from spacing, cover and bar size.
Reviewed formula · v1.0.0
Project inputs
Enter field measurements. Unit conversion happens before the reviewed formula is applied.
All values can be refined when you edit the estimate. This tool does not replace field verification or local requirements.
Transparent cost view
Use visible planning values, then replace them with actual job costs before quoting.
Material cost$30,005
Direct cost$30,395
Overhead + contingency$3,040
Markup + tax$4,012
Estimated project total$37,447
How this calculator works
A transparent slab rebar calculator takeoff.
This calculator lays a simple orthogonal rebar grid into a rectangular slab, using stated on-center spacing, edge cover and a published bar unit weight, then applies a visible lap-and-cut allowance.
Worked example. Example: a 20 ft × 12 ft slab with 18 in spacing both ways, 2 in edge cover and #4 bar needs 8 long bars and 14 cross bars. Net length is about 320.7 ft; with 10% allowance the purchase quantity rounds to 353 ft and about 236 lb.
- 1. Measure finished slab length and width.
- 2. Enter the specified on-center spacing, edge cover and bar size from the approved drawing.
- 3. Use the linear footage and weight as a supplier-planning input; laps, chairs, dowels and hooks need a detailed schedule.
Need the broader workflow? Read the concrete planning guide.
Questions
Common questions about this slab rebar calculator.
Does this design the reinforcement?
No. Bar size, spacing, cover, laps and development length must come from the responsible design. This tool only estimates a rectangular grid quantity.
Why is bar weight shown?
Rebar is often purchased by weight. Nominal unit weights follow published CRSI designations and remain visible so they can be replaced with mill data.