Rebar Calculator
Free rebar calculator. Enter slab size, bar spacing and size to get the number of rebar pieces, linear feet, weight in pounds, and ties for a reinforced concrete slab.
About the Rebar Calculator
Estimate reinforcement quantities from slab dimensions, spacing and the selected bar assumptions. This is a material-planning aid, not structural engineering design. Output includes the displayed bar and support estimates; it does not calculate wire-tie quantities or certify reinforcement suitability.
Features
- Slab grid estimate
- Bar spacing inputs
- Material-planning output
How to use this tool
The Rebar Calculator works right in your browser — no signup, no installation. Follow these steps:
- Enter the slab length and width in feet.
- Set the on-center rebar spacing (commonly 16 or 24 in).
- Pick the rebar size and tick lap if you are splicing.
- Read off bar count, linear feet, weight and ties.
Frequently asked questions
How does this tool work?
Estimate reinforcement quantities from slab dimensions, spacing and the selected bar assumptions. This is a material-planning aid, not structural engineering design. Output includes the displayed bar and support estimates; it does not calculate wire-tie quantities or certify reinforcement suitability.
Using the results
The Rebar Calculator estimates quantities from your measurements and the stated assumptions. Check dimensions, product coverage and project requirements before buying materials.