Rebar Calculator
Estimate rebar runs, total length, and pieces for slabs.
This page is an editable estimator with realistic defaults so you can model your own situation in minutes.
Rebar runs are based on slab dimensions and spacing, then multiplied by run length.
Treat the result as a planning estimate and verify important numbers with the relevant official source before acting.
| Spacing | 18 in | |
|---|---|---|
| Waste | 10% |
Assumptions
- Measure actual site dimensions before ordering.
- Waste factors, cuts, overlaps, compaction, and product coverage vary by material and installer.
- Confirm quantities with plans, local code, supplier guidance, and manufacturer instructions.
How this calculator works
Formula used
Rebar runs are based on slab dimensions and spacing, then multiplied by run length.
Example calculation
Plug in your own numbers and the result updates instantly. Rebar runs are based on slab dimensions and spacing, then multiplied by run length.
Rebar Calculator FAQ
Is this rebar calculator exact?
No. It is an estimating tool only. Actual quantities can change with field measurements, waste, layout, product dimensions, building codes, soil conditions, and installer methods.
Should I add extra material?
Usually yes. Many projects use a waste factor for cuts, breakage, overlap, spillage, grading, or mistakes. The best waste factor depends on the material and layout.
Should I verify before ordering?
Yes. Confirm quantities with your contractor, supplier, plans, local code requirements, and product installation instructions before purchasing materials.