Steel takeoff calculator
A member list in, a bill-of-steel ledger out. Enter each mark by AISC designation, length and piece count — the calculator matches the roster, applies the published weight per foot, and totals pounds, tons, pieces and lineal feet. Net weight, honestly labeled.
| Member | lb/ft | Pieces × length | Weight |
|---|---|---|---|
| W21X50 | 50 | 2 × 40 ft | 4,000 lb |
| HSS6X6X3/8 | 27.48 | 4 × 20 ft | 2,198 lb |
| Total | 6 pieces · 160 lineal ft | 6,198 lb3.10 tons | |
Net weight from published lb/ft — no waste, drops or connection allowance. Full roster: structural shape weights.
The ledger math
Every takeoff reduces to the same three-column ledger: count × length × unit weight, summed. The unit weight comes off the designation for W, C and MC shapes and from the AISC tables for angles, HSS and pipe. What this deliberately is not: purchased weight (add your shop's yield factor), connection material (designed details or your calibrated allowance), or anything a takeoff should flag rather than guess.
Common questions
- How do you calculate steel tonnage from a takeoff?
- Each line is count × length (ft) × the shape's published weight per foot; the total in pounds divided by 2,000 gives short tons. For W, C, MC, S and HP shapes the lb/ft is the second number in the designation — W21X50 weighs 50 lb/ft by definition. Angles, HSS and pipe need a table lookup, which this calculator does from the AISC roster.
- Is this net weight or purchased weight?
- Net weight — the steel that ends up in the structure. Purchased weight adds cut waste, drops and stock-length yield, and connection material adds plates, angles and bolts on top. Both are estimating judgement calls that vary by shop, so this ledger keeps them out and says so.
- How much does connection material add to a steel takeoff?
- It depends on the framing: simple shear connections add the least, braced frames more, moment frames the most. Estimators carry it as a percentage of member weight calibrated from their own completed jobs, or count it exactly once connections are designed. There is no honest universal number, which is why this calculator reports net member weight only.
- Can my AI assistant do this from a drawing?
- The same math is callable as an MCP tool (steel_takeoff_weight) on the StructuPath steel server. An assistant that has extracted a member schedule from a drawing can pass up to 500 lines and get the ledger back — weights per line, totals, and any designations it could not match.
Want these for yourself?
We can put these tools on your site, in your systems, or in front of your customers.
Everything here is something we built for ourselves first. If a calculator like this would earn its keep in your business, we build the same thing against your data and your brand.
On your website
Branded to your shop and hosted on your own domain. Reference tools are the reason people bookmark a fabricator's site — they come back for the chart and remember who published it.
Wired to your data
The same math running against your inventory, your mill certs and your job costs, so a takeoff pulls real weights from real material instead of a lookup table.
As internal tooling
Built into whatever your estimators already open. Fewer spreadsheets passed around, and one place where the numbers are known to be right.
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