Steel Nesting Calculator

Nest a steel cutting list into the fewest bars. Add the material you need to cut (with mark numbers), optionally list stock lengths you already have on the rack, and press NEST. You get a bar-by-bar cutting plan, the offcuts left over, and an order list of standard mill lengths with total weight. Everything runs in your browser and is saved locally – nothing is uploaded.

Lengths are entered in millimetres. Standard available lengths for each material type are pre-loaded below and fully editable to match what your supplier stocks.

Kerf is the material lost to each saw cut. End trim is removed from both ends of every bar (e.g. to square mill ends). Leftovers shorter than the minimum usable offcut are counted as scrap.

Methods: 2.1 packs each bar tightly one at a time. 2.2 re-runs 2.1 many times with shuffled orders and repairs the worst bars. 2.3 optimises the whole mix of cutting patterns at once (column generation) and reports how close to the mathematical minimum it got. 2.4 searches for the provably optimal nest – can take several seconds on big jobs. All methods use rack stock first and never do worse than 2.1.

Lengths in metres, comma separated, per material type (maximum 15 m). The nest only buys from this list. Delete lengths your supplier doesn’t stock; add any they do.

Hollow sections use per-size availability from the Surdex Steel reference guide automatically: 20/25 SHS 6.5 m only; 30–65 SHS and small RHS (50x20, 50x25, 65x35, 75x25, 102x76) 8 m only; larger SHS/RHS 8 and 12 m; 89 SHS also 9 m; CHS pipe 6.5 m; large structural pipe (≥168 OD) 9 and 12 m. The SHS/RHS/CHS rows above only apply to sizes outside that data.

Bars and offcuts already on your rack. The nest always uses these before buying new material.

The best result (least new material) is shown in bold and displayed below. Optimality compares against the mathematical lower bound where the method computes one.

Pieces are sorted longest first. Each piece is placed into the stock-on-hand bar it fills tightest (best-fit), so rack offcuts get used up before new material is bought. Whatever is left is then nested onto new bars: for every bar the calculator tries each available standard length and buys the one that leaves the least waste. Saw kerf is allowed for between every cut, and end trim is deducted from both ends of every bar.

This is the same greedy first-fit-decreasing approach used by most commercial linear nesting software – it is not guaranteed mathematically optimal, but is typically within a bar or two of optimal on real job lists. Pair it with the free Steel Quote take-off calculator to price the material it tells you to order.