Bar Bending Schedule (BBS): What It Is and How to Prepare One
A bar bending schedule (BBS) is the table that tells the steel fixers and the bar-bending yard exactly which reinforcing bars to cut and bend for a structure: how many of each bar, which diameter, what shape, how long, and how heavy. It is the link between the structural drawings and the steel that arrives on site. Many countries follow BS 8666 for the shape codes and the way dimensions are written.
What a bar bending schedule contains
| Column | What it means |
|---|---|
| Bar mark | A unique number or letter that links the schedule to the drawing (for example B12). |
| Member | The beam, column, slab or footing the bar belongs to. |
| Diameter | Nominal bar diameter in millimetres. |
| Number of members × bars per member | How many identical members, and how many of this bar in each. Multiply them for the total number. |
| Shape code and dimensions | The shape of the bar (straight, L, U, stirrup, crank…) and its dimensions A, B, C… |
| Cutting length | The straight length of steel that must be cut before bending. |
| Weight | Total number × cutting length × weight per metre. |
How to prepare one, step by step
- Go member by member. Read the drawing and list every bar of one beam, column or slab before moving to the next.
- Give every different bar its own mark, and re-use the same mark for identical bars on every member.
- Choose the shape from the standard shape table and write its dimensions in the same units as the drawing.
- Work out the cutting length from the shape: the sum of the dimensions, adjusted for the bends and hooks according to the standard you work to.
- Count the total number (members × bars per member).
- Calculate the weight with the unit weight of the diameter, and add a summary by diameter so the steel order is easy to place.
- Check against the drawing revision before the schedule is issued.
Mistakes that cost steel (and time)
- Forgetting laps, hooks or bar-end details that are in the general notes, not on the bar itself.
- Mixing millimetres and metres, or feet-inches, inside one schedule.
- The same mark used for two different bars, or two marks for the same bar.
- Rounding every cutting length up “to be safe”: over hundreds of bars it becomes tonnes of waste.
- Using a schedule that does not match the latest drawing revision.
Doing it in Excel
A spreadsheet is the usual tool, but formulas for every shape are long, easy to break and hard to check. BarFlow BBS is an Excel workbook that keeps the shape formulas inside: you type the bar mark, diameter, number and shape code with its dimensions, and it draws the real bar shape, calculates the cutting length and the weight, prints the schedule on A4 and exports it to DXF for AutoCAD. It works in English or Arabic, in millimetres or feet-inches. You can try it free: the free version has 30 ready shape codes, up to 20 rows and one bar diameter (12 mm).
Bar bending schedules in Excel and a rebar cutting plan, in English and Arabic. Both can be tried free.
BarFlow BBS (Excel)Cutting Plan (Microsoft Store)Pricing