Steel Estimating Knowledge Base
28 questions, answered the way an estimator would answer them: the short answer first, then the detail. Backed by the shape database and the steel calculator.
Steel Takeoff
What a takeoff is, how long it takes, and how counting really works.
- What is a structural steel takeoff?A structural steel takeoff is the process of reading the drawings and listing every steel member with its size, length and quantity. The result is a bill of materials that you price, order from, or hand to the shop. It answers "how much steel is on this job?" and nothing about cost.
- How long does a steel takeoff take?A manual steel takeoff runs from 2 to 4 hours for a small miscellaneous-metals job to 2 to 3 weeks for a large multi-story frame. Most small commercial jobs take one to three working days. AI-assisted takeoff cuts the extraction to minutes, then adds roughly 1 to 4 hours of human review on the same jobs.
- How do you count steel from drawings?Work sheet by sheet, identify every steel member callout, record its size and quantity, and mark it as counted so nothing is picked up twice. Where members are labeled with marks instead of sizes, resolve each mark through the schedule first. Then reconcile plans against schedules and details before you total.
- What's the difference between a takeoff and an estimate?A takeoff measures quantities: how many members, what sizes, how long, how heavy. An estimate takes those quantities and adds cost: material, shop labor, coatings, freight, erection, overhead and margin. The takeoff says how much steel there is; the estimate says what it will cost to supply.
Structural Steel Estimating
Tonnage, weight per foot, cost per ton and misc metals pricing.
- How do you calculate steel tonnage?Multiply each member's weight per foot by its length and quantity to get pounds, add the lines together, and divide by 2,000 for US tons. In metric, multiply kg per metre by length in metres and divide by 1,000 for tonnes. Always say which ton you mean: a short ton is 2,000 lb and a metric tonne is about 2,205 lb.
- How much does structural steel cost per ton?Raw structural steel material is commonly quoted somewhere around $900 to $1,600 per ton, depending on shape, mill versus service center, and delivery. Fabricated and erected, the all-in figure usually lands between about $2,100 and $4,000 or more per ton. These are typical ranges that move with mill pricing, region and job complexity, so use them as a starting point and get current quotes.
- What is steel weight per foot (plf) and how do you read it from W12x26?Weight per foot, written plf or lb/ft, is how many pounds one linear foot of a section weighs. In an AISC wide-flange designation like W12x26, the first number is the nominal depth in inches (12) and the second is the weight per foot (26 lb/ft). So a 20 ft W12x26 weighs about 520 lb.
- How do fabricators price miscellaneous metals?Misc metals are priced by unit (per flight of stairs, per linear foot of rail, per each) built up from shop hours, material, finish and installation, not by tonnage. They carry far more labor per pound than structural framing, so a cost-per-ton rate from beam work will underprice them.
Detailing & Drawings
Reading schedules, member designations and drawing set stages.
- How do you read a beam schedule or column schedule?A beam schedule is a table that lists each beam mark (B1, B2) with its size, camber, stud count and often connection or reaction data. The framing plan shows where each mark sits, and the schedule tells you what it is. A column schedule does the same for columns, listing the size at each level and the splice and base plate details.
- What does W10x15 mean?W10x15 is an AISC wide-flange beam: W for wide flange, 10 for a nominal depth of 10 inches, and 15 for a weight of 15 pounds per linear foot. The "x" is read as "by". A 20 ft piece weighs about 300 lb.
- What do HSS, L, C, MC and PL designations mean?HSS is hollow structural section (tube), written outside dimensions then wall thickness, like HSS6x6x1/4. L is an angle, written leg, leg, thickness. C and MC are channels, written depth then weight per foot. PL is a plate, written thickness then width.
- What are 30%, 60% and IFC drawing sets?They are stages of design completion. A 30% set is early design with approximate member sizes, a 60% set has most of the structure sized but still changing, and IFC (Issued for Construction) is the final set the work is built from. The earlier the set, the less reliable the takeoff.
International Standards
UK, Australian and European sections, and metric to imperial conversion.
- What is the UK equivalent of a W-beam (UB and UC)?The UK uses Universal Beams (UB) and Universal Columns (UC) in place of AISC W shapes. A UB is named depth x width x mass in millimetres and kg/m, like 305x165x40 UB. UB and UC sections are close to W shapes in purpose, but no UK section is an exact match, so a "UK equivalent" is a nearby substitute rather than the same piece of steel.
- How do Australian steel sections (UB, UC, PFC, SHS) work?Australian and New Zealand sections follow AS/NZS 3679.1 for hot-rolled sections and AS/NZS 1163 for hollow sections. Designations put the nominal size and the mass in kg/m together, like 250UB25.7 (a universal beam about 250 mm deep, 25.7 kg/m) or 100x100x6.0SHS (a 100 mm square hollow section, 6.0 mm wall).
- What are European IPE, HEA and HEB sections?IPE, HEA, HEB and HEM are European parallel-flange I and H sections defined in EN 10365. IPE is a lighter beam series, and HEA, HEB and HEM are progressively heavier wide-flange series used as beams and columns. The number after the letters is the nominal height in millimetres, so IPE 300 and HEB 300 are both about 300 mm tall.
- How do you convert kg/m to lb/ft?Multiply kg per metre by 0.67197 to get pounds per foot. To go the other way, multiply lb/ft by 1.48816. For example, an IPE 300 at 42.2 kg/m is 28.36 lb/ft, and a W12x26 at 26 lb/ft is 38.7 kg/m.
Revisions, Addenda & Change Orders
Keeping a bid honest when the drawings keep moving.
- How do you handle addenda and revisions in a steel bid?Log every addendum or revision the day it arrives, compare changed sheets against the set you priced, re-take-off only what changed, and state in your bid the exact revision of each sheet your number is based on. The risk is not the first takeoff, it is pricing one revision while the contract is awarded on another.
- How do you price a steel change order?Price a steel change order by taking off only the added or removed members, then applying material, shop labor, detailing, finish, freight and erection to that delta, plus the cost of rework and schedule impact. Document the quantities by drawing revision so the change can be checked against what you originally priced.
Software & Tools
AI takeoff, free tools, Bluebeam, scanned drawings and what it all costs.
- Is there AI steel takeoff software?Yes. AI steel takeoff software reads your structural drawings, finds the steel member callouts, and produces a bill of materials with sizes, counts and weights for you to review. SteelFlo does this for six standards (AISC, BS/IS, AS/NZS, EN, GB and cold-formed) and lets you try it on three of your own takeoffs for free.
- Is there free steel takeoff software?Yes, in three forms: a permanent free plan, a free trial, and free tools like spreadsheets and shape databases. SteelFlo's free plan gives you three AI takeoffs with no credit card, unlimited manual estimates and CSV export. Many other tools offer time-limited trials rather than an ongoing free tier.
- How much does steel takeoff software cost?It ranges from free to a few hundred dollars a month for steel-specific AI tools, and higher for enterprise contracts. SteelFlo's published prices: Free (3 AI takeoffs), a $99 one-time One-Job Pass (5 takeoff credits), Pro at $399 per month (10 takeoffs), Business at $599 per month (25 takeoffs), and Enterprise from $1,499 per month (60 takeoffs).
- Can you do a steel takeoff in Bluebeam?Yes, but it is a manual takeoff. Bluebeam Revu lets you mark up a PDF, count symbols, measure lengths and export the markup list to a spreadsheet, while you identify each member and type its size yourself. It has no built-in knowledge of steel shapes or weights, so weights and totals come from your own tables.
- Can AI read scanned steel drawings?Yes, to a useful degree. SteelFlo reads scanned and image-based PDFs as well as CAD-exported ones, boxes the member callouts it finds, and flags what it is unsure about for your review. Quality depends on the scan: sharp, high-resolution sheets read well, while faded, skewed or handwritten ones will need more manual checking.
Glossary
Short definitions of terms estimators and fabricators use every day.
- What is AESS (architecturally exposed structural steel)?AESS stands for architecturally exposed structural steel: structural members that stay visible in the finished building and are fabricated to a higher appearance standard than ordinary steel. The AISC Code of Standard Practice defines categories from AESS 1 to AESS 4 plus Custom, and the tighter the category, the more it costs to fabricate.
- What are miscellaneous metals (misc metals)?Miscellaneous metals are the fabricated steel items in a building that are not the primary structural frame: stairs, handrails and guardrails, ladders, bollards, lintels, shelf angles, embeds, gates and grating. In MasterFormat they fall under Division 05 50 00, Metal Fabrications.
- What are shear studs?Shear studs are headed steel stud anchors welded to the top flange of a steel beam so that the beam and the concrete slab on top act together as one composite member. They are counted per beam, usually shown in brackets after the beam size or in the beam schedule, and priced per stud.
- What is camber in a steel beam?Camber is a slight upward curve built into a steel beam so that, after the floor dead load is applied, the beam deflects down to level. It is specified in inches on the drawing or schedule, such as 3/4 in, and fabricators charge extra for it because the beam must be cold-bent or heat-cambered.
- What is a kip?A kip is a unit of force equal to 1,000 pounds-force. It is used in US structural engineering for loads, reactions and member capacities, so a beam reaction of 12 kips is 12,000 lb. A ksi is a kip per square inch, the unit for steel strength: A992 steel has a 50 ksi yield strength.
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