Column rebar quantity calculator
This calculator estimates column steel from the column concrete: section width × length × height × number of columns gives the volume, then volume × steel ratio (by default 120 kg per m³) gives the weight. Use it for early estimates; the exact quantity comes from the bar bending schedule.
Calculator
- Reinforcing steel
- 1,935 kg (1.94 t)
- Column concrete
- 16.13 m³
Method, step by step
- Multiply the section width by its length in metres to get the section area.
- Multiply by the column height and by the number of identical columns to get the concrete volume in m³.
- Multiply the volume by the steel ratio in kg per m³, then divide by 1000 for tonnes.
Worked example
Inputs
- Width (m): 0.3
- Section length (m): 0.7
- Column height (m): 3.2
- Number of columns: 24
- Concrete volume = width × length × height × count = 0.3 × 0.7 × 3.2 × 24 = 16.13 m³.
- Steel weight = volume × steel ratio = 16.13 × 120 = 1,935 kg.
- In tonnes: about 1.94 t.
Result
- Reinforcing steel
- 1,935 kg (1.94 t)
- Column concrete
- 16.13 m³
Assumptions and default ratios
| Ratio | Default value |
|---|---|
| Column steel ratio | 120 kg/m³ |
- The steel ratio is an editable default; it varies with column loads, number of floors and the design reinforcement ratio.
- Columns are assumed identical in section and height. Starter bars, laps between floors and waste are not included.
Frequently asked questions
How many kg of steel are there in one m³ of column concrete?
The default is 120 kg per m³, an estimate higher than for slabs because columns are usually more heavily reinforced. Adjust it to your design.
What if my columns have different sections?
Calculate each identical group (same section and height) on its own and add the weights, or add each group as its own BOQ line.
Does this replace the bar bending schedule?
No. The ratio is for early pricing and comparison; orders and payment certificates rely on the actual lengths in the schedule.
Add the result to your project BOQ in Ta3mir
In Ta3mir the same calculators work inside your project: send a result to a BOQ line in one click and save your own default ratios for every calculation.