Steel Take-Off: How to Estimate Steel Quantities From Drawings
How to do a steel take-off from structural drawings: listing members, calculating weights, connections allowance, waste factors, rebar schedules and common errors.
Saudi Steel Work Editorial Team · · 3 min read
Short answer: A steel take-off lists every member from the drawings by profile and length, multiplies length by the section's weight per metre, adds plates and connections (often 5–15% of main member weight depending on the structure), and applies a waste allowance before ordering.
Accurate quantities are the foundation of a good steel budget and RFQ. Under-ordering delays the job; over-ordering ties up cash and site space. Here is a practical method.
Step 1 — Organise the drawings
Work through plans, elevations and sections systematically: columns, beams, bracing, purlins and girts, then secondary steel (stairs, platforms, handrails), then plates and connections.
Step 2 — List members by profile
For each member type record profile, grade, length and count:
| Mark | Profile | Grade | Length (m) | Qty | kg/m | Weight (kg) |
|---|---|---|---|---|---|---|
| C1 | HEB 300 | S355JR | 8.5 | 24 | 117 | 23,868 |
| B1 | IPE 400 | S355JR | 9.0 | 36 | 66.3 | 21,481 |
| BR1 | CHS 114.3×6 | S355J2H | 7.2 | 48 | 16.0 | 5,530 |
Use section tables or our steel weight calculator for kg/m values.
Step 3 — Plates and connections
Base plates, end plates, cleats, stiffeners and gussets add significant weight. Where connection details are available, measure them. Where not, apply an allowance agreed with your estimator — commonly in the 5–15% range of main member weight depending on structure type.
Step 4 — Bolts and consumables
List bolts by grade, diameter and length, plus anchor bolts. Welding consumables are usually estimated by the fabricator.
Step 5 — Flat and tubular items
For plates, compute area × thickness × 7.85 (plate weight). For pipes, use the pipe formula (pipe weight).
Step 6 — Rebar
Rebar is normally quantified from a bar bending schedule: diameter × total length × kg/m. See bar bending schedule guide and the rebar weight calculator.
Step 7 — Waste and stock lengths
Members rarely use full stock lengths. Group lengths to minimise offcuts (for example, two 5.8 m pieces from a 12 m bar). Add a waste factor appropriate to the item and how well lengths can be optimised.
Common errors
- Mixing European and British section weights
- Forgetting galvanizing weight on large tonnages
- Counting members once when they repeat on multiple gridlines
- Ignoring secondary steel and miscellaneous metalwork
From take-off to quotation
Once your take-off is complete, convert it into an RFQ (how to write a steel RFQ) or send it to us — a spreadsheet is the fastest way to get an accurate price.