Reinforcement Take-Off: Working Out Rebar Quantities for Ordering

Reinforcement is ordered by tonnage and, ultimately, cut and bent to a bar schedule. But the take-off starts earlier, from the element volumes and the reinforcement rates, and lands on a quantity of steel by bar size that the buyer orders against. This page is about getting that quantity right, supplier-neutral, before it becomes a purchase order.

How a reinforcement quantity is derived

Reinforcement quantity comes from the structural design: a rate of steel per cubic metre of concrete (or per element), split by bar diameter. A pad foundation carries a mat of bars; a strip footing carries longitudinal and transverse steel; a headwall carries steel in the back wall, apron and wing walls. The take-off applies the rate to each element and totals the steel by bar size, because that is how reinforcement is priced and ordered.

Tonnage versus bar schedule

Two documents get confused here, so be clear about scope.

• A reinforcement take-off is the quantity of steel, by bar diameter, for ordering and pricing. It answers "how much 16 mm bar, how much 12 mm".
• A bar-bending schedule is the fabricator's detailed cut-and-bend list: every bar mark, its shape, its cutting length and bending dimensions to BS 8666.

The take-off feeds the order and the BoQ rate; the detailed cut-and-bend schedule is a downstream document. CivilQuants gives you the take-off by bar size, with bar marks and BS 8666 shape codes attached, which is most of the way to a schedule, but the formal cut-and-bend detailing stays with the design and the fabricator.

Worked example: a pad foundation

Take a reinforced pad foundation at its default dimensions. The reinforcement take-off, by bar size:

That total, 0.1214 t in roughly 1.8 m³ of concrete, is the number you order and price against, split by diameter so the supplier quotes each bar size correctly. The take-off keeps the diameters apart for the same reason the concrete take-off keeps grades apart: a single blended tonnage cannot be priced or cut.

From quantity to order

Reinforcement is supplied in stock lengths and cut to suit, so the order carries cutting waste and lap allowances on top of the net tonnage. The buyer takes the net take-off by bar size, adds a defensible allowance for laps and offcuts, and rounds to the supplier's stock and minimum-order terms. As with concrete, the tonnage is supplier-neutral: it is what to order, not who from.

Why derive it rather than estimate it

A reinforcement guess as a flat rate across the whole job hides which bar sizes you actually need and has to be redone on every revision. A take-off derived from the element geometry returns the tonnage by diameter, deterministically, and re-runs when the design changes. For the concrete that goes around the steel, see a concrete take-off; for the full list, a full material take-off.

Disclosure: CivilQuants is our product. It returns reinforcement by bar size, with bar marks and BS 8666 shape codes, from the assembly parameters, with an audit trail and supplier-neutral. It measures quantities and never rates, and it does not produce a stamped structural design or place orders.

Illustrative figures at the calculator's default dimensions (pad foundation engine ref 714d4c). Not a tendered quantity; verify against your design.

FAQ

How much rebar do I need for a pad foundation? At the calculator's default dimensions, about 0.1214 t in total, split roughly 0.0097 t of 10 mm, 0.0337 t of 12 mm and 0.0780 t of 16 mm bar. Your own design will differ; the take-off splits it by diameter so each is priced and ordered correctly.

Is this a bar-bending schedule? No. It is the reinforcement take-off by bar size, with bar marks and BS 8666 shape codes. A formal cut-and-bend schedule, with every cutting length and bending dimension, is a separate detailing document from the design.

How is reinforcement measured in a BoQ versus for ordering? Both work from the same tonnage by bar diameter. In a CESMM BoQ it sits in the reinforcement class, measured by tonne per diameter; for ordering it is the same tonnage, plus stock-length, lap and wastage allowances.

How do I allow for laps and wastage on rebar? Add a lap allowance where bars are spliced and a cutting-waste allowance for offcuts to the net tonnage, then round to the supplier's stock lengths and minimum order. Keep the allowance defensible rather than a blanket percentage.

Does the take-off price the steel? No. It gives the tonnage by bar size, supplier-neutral. You apply your own supplier rate.

Try it

Get a reinforcement take-off free: the headwall calculator renders to MMHW in the browser with no sign-up and the full catalogue has five more free assemblies. The pad foundation calculator carries the worked example above. When you need all four standards and clean Excel, DXF and PDF deliverables, the 7-day pass is £15 on the pricing page.