Rebar Calculator
Estimate rebar bars and 20ft sticks for a slab grid layout.
20ft rebar sticks needed
8 sticks
- Total linear feet (with waste)
- 154 ft
- Bars one direction
- 7
- Bars other direction
- 7
How we calculate this
For a grid layout, bars in each direction = floor(perpendicular dimension ÷ spacing) + 1. Total linear feet = (bars one way × length) + (bars the other way × width), then divided by the standard 20 ft stick length to get sticks needed.
Example
Measuring tips
Common residential slab spacing is 12–18 inches on center. Check your local code or engineer's specification for load-bearing slabs.
Common mistakes
- Using too wide a grid spacing for load-bearing applications.
- Forgetting overlap/lap length when joining rebar sticks, which adds to material needed.
- Not confirming rebar size (e.g. #3 vs #4) requirements with local code.
Frequently asked questions
How far apart should rebar be spaced?
12–18 inches on center is common for residential slabs — always confirm with local code for your specific application.
How long is a standard rebar stick?
Rebar is commonly sold in 20 ft lengths, which this calculator uses to compute sticks needed.
Related calculators
Estimates are provided for planning purposes. Actual material requirements may vary based on supplier specifications, compaction, site conditions, installation method, waste, and local code. This calculator does not provide engineering certification or structural approval.