Rebar Stock Cutting Calculator
Segments, offcut, purchase quantity and utilisation.
Inputs
Result
Formula
| Segments = floor((stock + kerf) ÷ (need + kerf)) | |
| Offcut = stock − n×need − (n−1)×kerf | |
| Bars to buy = ceil(pieces ÷ segments) | |
| Utilisation = finished length ÷ (bars × stock) |
3.5 m pieces, 500 of them, on 12 m stock: 3 per bar with 1.5 m left, 87.3% utilisation, 167 bars. On 9 m stock: 2 per bar with 2 m left, 250 bars, and utilisation drops to 77.8%.
FAQ
Why is longer stock more efficient?
Each bar carries a fixed offcut. Cutting 3.5 m on 12 m yields 3 pieces and 12.5% waste; on 9 m only 2 pieces and 22%. Longer stock means more segments and a smaller waste fraction. But it turns bad when the piece approaches half the stock: 6.5 m on 12 m gives one piece and 46% waste - lap it or change the stock.
Can offcuts be counted as usable material?
Only if some component needs that length - 1.5 m pieces suit stools, ties and short stirrups. Otherwise they are scrap at roughly a quarter of the bar price. List offcuts first, see what can absorb them, then choose stock length. That is where bar-bending yards actually save money.
Why count kerf loss?
Every cut removes 3-10 mm (more with an abrasive saw). Three pieces from one bar mean 2 cuts, or 4 if both ends are trimmed - 20-40 mm of loss. Trivial per bar, it becomes 20-40 m over a thousand. For precision work such as coupler splices with square-cut ends, it must be included.
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Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.