STEEL
Steel Weight Calculator: TMT Bar Weight (D²/162)
How to calculate steel weight: D² ÷ 162 kg per metre for 6 to 32 mm bars, bar list by diameter, 12 m rods to buy, cost per kg, and a quick estimate.
Bars
240.0 m · 213.3 kg
180.0 m · 71.1 kg
Assumptions used VIEW ▾
Weight per metre = D² ÷ 162 kg, where D is the bar diameter in mm (from steel density 7,850 kg/m³). Lengths should include laps, bends and hooks as per the bar bending schedule. Actual rolling weight can vary by a few percent.
TOTAL STEEL
284kg
0.284 tonne
- 8 mm180.0 m · 15 rods of 12 m · 0.395 kg/m
- 71.1 kg
- 12 mm240.0 m · 20 rods of 12 m · 0.889 kg/m
- 213.3 kg
Bar weight table (D² ÷ 162)
| Dia | kg / m | kg / 12 m rod |
|---|---|---|
| 6 mm | 0.222 | 2.67 |
| 8 mm | 0.395 | 4.74 |
| 10 mm | 0.617 | 7.41 |
| 12 mm | 0.889 | 10.67 |
| 16 mm | 1.580 | 18.96 |
| 20 mm | 2.469 | 29.63 |
| 25 mm | 3.858 | 46.30 |
| 32 mm | 6.321 | 75.85 |
How it’s calculated
Weight per metre = D² ÷ 162 kg (D in mm)
Example: 20 bars of 12 mm, 12 m long: 240 m × 0.889 kg/m = 213.3 kg.
Questions
How do I calculate the weight of a steel bar?+
Square the diameter in mm and divide by 162 to get kg per metre, then multiply by the total length. A 12 mm bar weighs 144 ÷ 162 = 0.889 kg per metre.
Where does D² ÷ 162 come from?+
Steel weighs about 7,850 kg per m³. The area of a round bar of D mm times 1 m of length times that density works out to D² ÷ 162 kg.
How much steel per m³ of concrete?+
As a rough guide: slabs about 80 kg, beams about 130 kg, columns about 160 kg and footings about 70 kg per m³. The structural drawing decides the real figure.
Estimates for planning, based on the assumptions shown. They are not a guarantee of quantities or professional engineering advice; check critical work with a qualified professional.