Linear Cutting Calculator | NestingCalc

Linear cutting is the one-dimensional cutting stock problem: given a parts list and stock lengths, find the combination that fills every order from the fewest bars. It is deceptively hard — with 30 parts and mixed lengths, brute-force enumeration is astronomically large — so the engine uses a proven heuristic, best-fit decreasing: parts are sorted longest first (higher priority first), and each one goes into the bar where it leaves the smallest remainder.

The result is deterministic: the same list returns the same plan every run, which is what makes it usable for quoting. You control the physical rules — kerf width, trim, which offcuts count as reusable stock — and the plan respects them exactly. The math and its history are covered in The Cutting Stock Problem, Explained Simply.

Each cut removes the blade's width from the bar. Cutting two 2.95 m parts from a 6 m bar: 2 × 2.95 + one 5 mm kerf = 5.905 m — fits, with a 95 mm remnant. Ignore the kerf and you expect 100 mm back; plan a 3.0 m part from the offcut and it fails at the saw.

Across a full list the effect compounds: a 40-part order cut with a 3 mm versus 5 mm blade differs by 40 × 2 mm = 80 mm of pure sawdust — often the difference between 9 and 10 bars. The same applies to trim cuts that square a bar's end. Set both in the calculator's settings to match your actual machine; What Is Kerf? Why Every Cut List Needs It details how kerf interacts with nesting on sheets.

Optimizing only works against the lengths your supplier actually sells. Typical catalog values — always confirm with your stockist, because mills differ:

Not sure which length to buy? Enter the alternatives in the comparison field: the tool solves the same list against each stock length and ranks them by bars used, then waste — often a different length beats the one you always order. Reusable offcuts from earlier jobs can be added as extra stock, and the optimizer cuts from them alongside new bars.

Deck order: 14 posts of 1.20 m in steel tube, stock bars of 6 m, saw kerf 4 mm. Parts per bar: 4 × 1.20 + 3 × 0.004 = 4.812 m, leaving a 1.188 m remnant — 4 posts per bar. Three bars cover 12 posts; the fourth bar takes the last 2 posts and yields a 3.59 m offcut, comfortably reusable.

The naive plan — one length per bar ordered by size — needs the same 4 bars but ignores that the last bar's 3.59 m offcut is stock, not scrap. Enter it as available stock in the next job and it disappears from the purchase list. That habit alone typically trims 5–10 % from recurring bar orders.

The cheapest bar is the one already paid for. The calculator's offcut inventory keeps remnants from previous jobs as stock: a remnant enters once, with its real measured length, and every new plan consumes it before new bars.

Shop-floor rules that make it work: set a reuse threshold (steel remnants below ~1 m rarely pay for their handling; aluminium below ~0.5 m), measure the remnant after the cut — not the theoretical leftover — and label it. An unlabelled 1.9 m bar in the rack is scrap; a labelled one is money. Every remnant consumed is a bar not bought, cut, delivered and stored.

Recommended flow: (1) freeze the parts list at final cut length; (2) run the optimizer with real kerf and trim; (3) print the per-bar plan; (4) cut in sequence, bundling each bar's parts with its label; (5) measure and record leftover lengths back into the offcut inventory.

For sheet goods the same discipline applies in two dimensions: the Sheet cutting calculator plans panel cutting the way this one plans bars. Guide 7 Ways to Reduce Cutting Waste in Your Workshop covers the broader waste-reduction playbook; The Cutting Stock Problem, Explained Simply explains the underlying cutting stock math.