MyYardCalcHow to use this rebar calculator
Enter the spacing, cover and lap length from your design. This tool counts a single orthogonal mat and does not choose reinforcement for loads.
Stock is counted separately for each run, allowing the entered lap at splices. Offcuts are not reused, so a detailed cutting schedule can reduce the order.
Runs = ceil(usable perpendicular span ÷ spacing) + 1. Spliced stocks per run = ceil((run − lap) ÷ (stock − lap)).
A worked example
With the example values shown below, the calculated result is 38 bars. These are demonstration inputs, not installation specifications.
View the example measurements
- Slab length: 20 ft
- Slab width: 12 ft
- Maximum grid spacing: 12 in
- Edge cover: 3 in
- Stock bar length: 20 ft
- Splice overlap: 24 in
- Extra allowance: 10 %
From estimate to order
Whole packages and pieces round up; measured lengths, areas and volumes keep full precision during calculation. Match the product dimensions and units to your quote, and check cuts, minimum orders and delivery before purchasing.