Rebar Calculator
Rebar length and tie count for a slab.
Reviewed by James Whitfield · How we check our maths
Your values
ⓘ Live results
Results
- Total rebar length
- 431.2 ft
- Bars lengthwise
- 10
- Bars widthwise
- 16
- Tie wire intersections
- 160
- Estimated cost
- $366.52
Quick answer
Rebar count comes from slab dimensions divided by grid spacing in each direction, plus overlap allowance.
Worked example
Worked example
Using the values the calculator loads with.
Inputs
- Slab length20 ft
- Slab width12 ft
- Grid spacing16 inches
- Price per foot0.85 $
Result
- Total rebar length431.2 ft
- Bars lengthwise10
- Bars widthwise16
- Tie wire intersections160
- Estimated cost$366.52
How to use the Rebar Calculator
- 1Enter slab length and width.
- 2Choose grid spacing (12, 16 or 18 inches).
- 3Order 10% extra for laps.
Frequently asked questions
How much overlap at splices?
At least 40 bar diameters — about 20 inches for #4 rebar.
Where should rebar sit?
In the middle third of the slab, on chairs, not on the ground.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error