Rebar Calculator
Estimate reinforcing-bar grid lines, linear feet and stock-bar quantity for rectangular slabs.
Why use this rebar calculator?
Rebar Calculator estimates a rectangular reinforcing grid from slab dimensions and bar spacing.
Example
For a 30 × 20 ft slab at 12-inch spacing, estimate total grid lines, linear feet and 20-ft stock bars.
Important note
Structural reinforcement size, spacing, cover, laps and detailing must follow the project design. This tool estimates quantity only.
How to use it
Start with the inputs shown above, review the assumptions or options, then generate the result. Where the tool creates a file, keep the original until you have opened and checked the downloaded output.
Frequently asked questions
Is Rebar Calculator free?
Yes. The core tool is free to use without creating an account.
Do I need an account to use Rebar Calculator?
No. You can use the core Toolbox workflow without signing up.
Does Rebar Calculator work on mobile?
Yes. Toolbox is designed for modern mobile and desktop browsers, although complex file workflows can be easier on a larger screen.