REBARCALCPRO

BAR BENDING SCHEDULE

Free BBS calculator — cutting length & steel weight to BS 8666:2020

Project Details

Select Shape Code

Code 00
L = A CODE 00
Official BS 8666:2020 shape diagram where available; schematic fallback otherwise. Not to scale for tolerancing.

Enter Bar Details

BS 8666:2020
BS 8666:2020 · SHAPE 00 LENGTH EQUATION
L = A
Cutting length, L 0 mm
0.222 kg/m (nominal mass, BS 4449)
0.00 kg, this line total

Bar Bending Schedule

Rows are grouped by Description, matching a standard printed BBS (toggle this in Schedule settings). Tip: open the exported .xlsx directly in Google Sheets via File → Import → Upload, or in Excel.
MarkTypeSizeNo. of setsNo. per setTotal no.Length (mm)Bar shapeWeight (kg)ABCDEFRq
No bars added yet — fill in the form above and click "Add to schedule".

Symbols

BS 8666:2020 — Table 1
dNominal size (diameter) of the bar
DDiameter of the mandrel (bending former)
rMinimum radius for scheduling (see Table 2)
RSpecified actual bend radius, where different from the minimum r
PMinimum end projection of a bent bar beyond the last bend (see Table 2)
qHook allowance for a 180° hook (see Table 2)

Minimum Scheduling Radii, Former Diameters & Bend Allowances

BS 8666:2020 — Table 2
r = minimum radius for scheduling. 2r = minimum diameter of bending former. P = minimum end projection (general bend, or link bend >150°, and link bend <150°). q = hook allowance for a 180° hook. Unit weights (kg/m) are nominal mass per metre values consistent with BS 4449. All dimensions in mm.

Standard Deductions Between Two Concrete Faces

BS 8666:2020 — Table 3
Distance between concrete faces (mm)Deduction (mm)
≤ 2005
≤ 40010
≤ 1 00015
≤ 2 00020
> 2 00030
An additional 10 mm should be deducted when determining the cutting length of straight bars whose ends are to be placed between concrete faces.

Minimum Allowances Between Two Bends

BS 8666:2020 — Table 4
Nominal bar sizeMinimum value of X
≤ 16 mm10d, but not less than 75 mm
> 16 mm13d
For all shapes with two or more bends (in the same or opposite direction, whether in the same plane or not), the overall dimension on the schedule must always include a minimum straight of at least 4d between the curved portions of adjacent bends — X is that minimum straight length.

Standard Bar Lengths, Laps & Assumptions

Reference — not part of BS 8666

Standard stock bar length

Reinforcing bar is most commonly stocked and supplied in 12 m straight lengths, with 6 m and other lengths (up to ~15 m) available to special order from some suppliers. This calculator schedules the cutting length of each bar mark only — it does not automatically split long bars against a stock length or optimise offcuts, so check the total cutting length of any mark against your supplier's available stock length before ordering.

Lap length quick reference

Lap and anchorage lengths are a structural design matter — governed by BS EN 1992‑1‑1 (Eurocode 2) and the project specification — and fall outside the scope of BS 8666, which covers bar shape and bending only. This calculator does not add lap length automatically. The indicative tension laps below are for Grade B500 ribbed bar in normal-weight concrete, and are starting points for take-off only — the project structural drawings give the binding values.
Bar sizeTension lap
good bond, C30/37		Tension lap
poor bond		Common rule of thumb
10 mm~400 mm (40d)~575 mm (58d)40d common; 50d safe
12 mm~480 mm (40d)~690 mm (58d)40d common; 50d safe
16 mm~640 mm (40d)~920 mm (58d)40d common; 50d safe
20 mm~800 mm (40d)~1150 mm (58d)50d for safety in pile caps
25 mm~1000 mm (40d)~1450 mm (58d)Often 50–55d on drawings
32 mm~1280 mm (40d)~1855 mm (58d)Always defer to engineer
40 mm~1600 mm (40d)~2320 mm (58d)Couplers usually preferred
Bond conditions. “Good bond” applies to bars more than 250 mm from the top of a pour, or in the bottom of pours less than 250 mm deep. Top bars in deeper pours sit in poor bond conditions and need the larger lap. Eurocode 2 lap lengths also depend on the percentage of bars lapped at the section, cover, transverse reinforcement and concrete class; the values above assume up to 50% of bars lapped in C30/37 with normal cover. Always take the binding value from the project’s structural drawings or a design check, not from this table.

Assumptions & notes

  • Cutting lengths use the BS 8666:2020 Table 5 formula for each shape code and do not include any allowance for laps — add extra length yourself if a mark needs to include a splice.
  • Bend allowances, minimum radii and hook allowances (Table 2) assume standard, non‑seismic detailing.
  • Unit weights are nominal mass per metre (consistent with BS 4449), not a BS 8666 table; actual delivered bar weight can vary within normal manufacturing tolerance.
  • No deduction for concrete cover is made automatically — enter dimensions A–F already net of cover if that's how your drawing is dimensioned.
  • No cutting wastage/offcut allowance is added automatically — apply your own project wastage percentage for procurement quantities.
  • This tool assists with scheduling only. Always check the finished schedule against approved structural drawings before fabrication.

Sources & References

Standards consulted
The formulas, tables and values used by this calculator are drawn from the following published standards. This tool reproduces no part of these standards; it applies their methods. Consult the source documents for the authoritative text.
  • BS 8666:2020 — Scheduling, dimensioning, bending and cutting of steel reinforcement for concrete — Specification. British Standards Institution. Source of the 37 standard shape codes, the cutting-length formulas (Table 5), minimum scheduling radii, mandrel diameters and end projections (Table 2), the symbols (Table 1), standard deductions between concrete faces (Table 3), and minimum allowances between bends (Table 4).
  • BS 4449:2005+A3:2016 — Steel for the reinforcement of concrete — Weldable reinforcing steel — Bar, coil and decoiled product — Specification. British Standards Institution. Source of the steel grades (B500A, B500B, B500C) and the nominal mass-per-metre values used for weight calculation.
  • BS EN 1992-1-1 (Eurocode 2) — Design of concrete structures — General rules and rules for buildings. Source of the lap length and anchorage principles referenced in the lap length quick reference. Lap lengths are a design matter and are not calculated by this tool.
  • BS 8666:2020, Clause 8 — Tolerances on cutting and bending dimensions, referenced in the assumptions and notes above.
Disclaimer. This calculator is an aid to scheduling and take-off. It is not a design tool, and it is not a substitute for a checked, engineer-approved bending schedule. Values produced here must be verified against the approved structural drawings and project specification before any steel is cut, bent or ordered. Where this tool and a project document disagree, the project document governs. Standards are periodically revised — confirm you are working to the edition current for your project.