Steel Cut List Optimizer: From Takeoff to Order
A steel cut list optimizer takes the pieces you need (size, length, quantity) and fits them onto the stock lengths you can buy, allowing for saw kerf, so you order the fewest sticks with the least scrap. It's one-dimensional nesting. The hard part is rarely the math. It's getting a clean cut list out of the takeoff in the first place.
What is a steel cut list optimizer?
In fabrication, a cut list is every piece you'll cut, grouped by section: "HSS6x6x1/4, 12 @ 11'-4"." An optimizer, sometimes called a linear nesting or 1D cutting tool, takes that list plus the stock lengths available (20, 24, 40, 48 ft and so on) and returns a cutting plan: which pieces come out of which stick, and what's left over.
The output you care about as an estimator or buyer:
- Sticks to order per section and length
- Ordered weight (what you pay for) versus net weight (what ends up in the building)
- Drops, the leftover length on each stick, and whether any are long enough to keep
- Waste % to replace the flat 10% you'd otherwise guess
Generic optimizers are mostly built for lumber, aluminum extrusions and closet shelving. They work fine for steel, but they don't know anything about your takeoff. You re-key every line, and that's where transposition errors creep in.
If you're still building cut lists by hand off the drawings, upload the set to SteelFlo. The Order Sheet nests your takeoff against stock lengths on export, so there's nothing to re-type. The first 3 takeoffs are free.
What data do you need to go from takeoff to cut list?
A takeoff count alone isn't enough to nest. For each line you need:
| Field | Example | Where it comes from |
|---|---|---|
| Section | HSS6x6x1/4 | Plan callout or schedule |
| Grade | A500 Gr. C | General notes or specs |
| Cut length | 11'-4" | Measured off plan, elevation or schedule, plus connection allowances |
| Quantity | 12 | Count from the drawings |
| Mark (optional) | C-3 | Schedule or your own numbering |
| Finish (optional) | Galvanized | Notes, so you don't nest painted and galv pieces together |
Two things trip people up.
Cut length isn't the grid dimension. A beam spanning 30'-0" center to center of columns is shorter by the column half-depths and connection setbacks. For bid purposes many estimators use grid length and accept a small overrun. For an order, use detailed lengths if you have them.
Grade and finish split the nest. Don't nest A500 Grade C with A500 Grade B, or galvanized pieces with primed ones, unless you're truly going to buy and process them the same way.
The bill of materials guide covers how to structure these fields so the BOM, cut list and order sheet stay in sync.
Which stock lengths, kerf and drop rules should you use?
These are the inputs that change the answer most:
| Input | Typical value | Notes |
|---|---|---|
| W-shape stock | 40, 60 ft (50 and 65 in some markets) | Check your mill or service center |
| HSS stock | 20, 24, 40, 48 ft | 24s and 40s common; availability varies by size |
| Angle, channel | 20, 40 ft | 20s dominate at service centers |
| Pipe | ~21 ft and ~42 ft | Single and double random lengths |
| Saw kerf | about 1/8" to 1/4" per cut | Band saws on the low end; use your shop's real number |
| End trim | 0 to 2" per stick | If supplier cuts run rough or ends are damaged |
| Minimum usable drop | 3 to 6 ft | Shorter than this usually ends up as scrap |
Mill tolerances on length and straightness are set by ASTM A6 for rolled shapes, so a "40-foot" stick isn't always 40'-0" exactly. Most shops add a little end trim for that. Our stock lengths and drops guide has more on regional availability, and waste factors in steel fabrication gives typical waste by member type when you don't have time to nest.
Should you use a standalone 1D optimizer or nest inside your takeoff tool?
Both work. The difference is where the data comes from and how many times you type it.
| Standalone 1D optimizer | Nesting in the takeoff tool | |
|---|---|---|
| Input | You enter or paste pieces and stock | Pulled from the confirmed takeoff |
| Steel awareness | Generic lengths and materials | Grouped by section, with weights per foot |
| Ordered weight | You calculate it | Calculated from the section |
| Change handling | Re-enter or re-import after every revision | Re-export after you update the takeoff |
| Best for | Shop cutting plans, inventory remnant use | Bid-time order quantities and purchasing |
Some real options, as of September 2026 (check each vendor's site for current features and pricing):
- Cutlistor's free linear cut list optimizer runs in the browser with no login, supports kerf, and handles a single stock length on the free version, with multiple materials in paid plans.
- 1D Stock Cutter is downloadable software that handles mixed stock lengths, inventory and order lists, with a 30-day trial or limited free version.
- Fabrication MIS and production software often includes nesting tied to inventory and remnants. Our fabrication software buyer's guide covers that category.
- Takeoff tools with built-in nesting, such as SteelFlo, produce an order sheet straight from the takeoff.
A standalone optimizer is great when you need to plan cuts from yard remnants, or when you already have a clean list. If your list starts on the drawings, nesting at export saves a whole re-keying step. If you do move data between tools, the export and integrations post shows the CSV and Excel formats.
Worked example: nesting 38 HSS pieces
A canopy and entry frame package calls for 38 pieces of HSS6x6x1/4 (19.02 lb/ft):
| Mark | Qty | Cut length | Line total (ft) |
|---|---|---|---|
| P1 | 8 | 14'-2" | 113.3 |
| P2 | 12 | 11'-4" | 136.0 |
| P3 | 10 | 8'-9" | 87.5 |
| P4 | 8 | 5'-6" | 44.0 |
| Total | 38 | 380.8 ft (7,243 lb net) |
Nest it three ways with 1/4" kerf per cut, using a first-fit-decreasing approach (longest pieces placed first):
| Stock | Sticks | Ordered (ft) | Ordered (lb) | Waste % |
|---|---|---|---|---|
| 20 ft only | 25 | 500 | 9,510 | 23.8% |
| 24 ft only | 17 | 408 | 7,760 | 6.7% |
| 40 ft only | 10 | 400 | 7,608 | 4.8% |
The 20-foot result is the lesson here. A 20-foot stick minus an 11'-4" cut leaves 8'-8". The P3 pieces are 8'-9", so they miss by an inch, and all eight P4s are already paired with the 14'-2" cuts. Twelve sticks each throw away an 8'-8" drop. A flat 10% waste factor would have under-ordered this package by more than 1,500 lb.
The 40-foot nest is tightest, and it leaves a couple of 4 to 5 foot drops that might cover a stray P4 on the next job. In practice you'd also check:
- Handling and freight. 40-foot HSS needs a longer trailer and two people or a forklift with extensions. Some small shops prefer 24s even at a slight waste premium.
- Availability. If your service center stocks HSS6x6x1/4 in 24s and 40s, mixing them can beat either one alone.
- Price per pound by length. Some suppliers charge a cut or short-length premium. Compare the extended cost, not just pounds.
Now picture this across 40 different sections on a real job. That's why nesting by hand rarely happens at bid time, and why most bids carry a flat waste factor that's wrong in one direction or the other.
How do you turn the nest into a mill or service-center order?
Once you've nested, the order is a summary by section and stock length:
| Section | Grade | Stock length | Sticks | Weight (lb) |
|---|---|---|---|---|
| HSS6x6x1/4 | A500 Gr. C | 40 ft | 10 | 7,608 |
| W16x26 | A992 | 60 ft | 12 | 18,720 |
| L4x4x3/8 | A36 | 20 ft | 6 | 1,176 |
(The W16x26 and angle lines are illustrative, carried over from a separate nest.)
Before you send it:
- Confirm stock lengths with the supplier. What's on the shelf this week may differ from the catalog.
- Ask about mill test reports if the job requires them, so they ship with the material.
- Flag finish. If galvanizing comes after fabrication, nothing changes on the order. If you're buying pre-galvanized or pre-primed stock, say so.
- Keep the drop list. If your nest leaves usable drops, log them in inventory with the job number so they get used.
- Re-nest after revisions. An addendum that changes six beam lengths can change the stick count. This is where a takeoff-linked nest pays off: update the takeoff and re-export.
For section weights and properties, the AISC Shapes Database is the reference. You can also look up any shape on our HSS sizes guide or the free shapes pages.
Frequently Asked Questions
What is a cut list optimizer for steel?
It's software that fits your required piece lengths onto available stock lengths, allowing for saw kerf, to minimize the number of sticks you buy and the scrap you throw away. It's also called linear or 1D nesting. The output is a cutting plan plus an order quantity.
What kerf should I use for steel cut list optimization?
Use your shop's measured saw kerf, typically about 1/8" to 1/4" per cut for band saws. Add an inch or two per stick for end trim if your supplier's ends run rough. Kerf matters most when pieces nest almost exactly into a stock length.
Is a flat 10% waste factor good enough?
It's fine for early budgets, but it can be wrong by a lot in both directions. In the HSS example above, true waste ran from about 5% on 40-foot stock to nearly 24% on 20-foot stock for the same 38 pieces. Nest the big-ticket sections and use a flat factor only for the small stuff.
Can I nest steel in Excel?
You can, for a handful of pieces, but it gets painful fast and formulas don't handle mixed stock lengths well. A dedicated optimizer or a takeoff tool with built-in nesting does it in seconds and is easier to re-run after revisions.
What is the difference between a cut list and an order sheet?
A cut list is every piece you'll cut, by section, length and quantity. An order sheet is what you buy: sticks per section and stock length, with weights. The nest is the step that turns one into the other.
Bottom line
The optimizer math is a solved problem. What costs you time is the step before it: getting a clean, counted, measured list off the drawings, then retyping it into another tool. SteelFlo's Order Sheet nests the takeoff against stock lengths when you export, so you can go from PDF to purchase order in one place and spend your review time on the lengths that matter.