Steel Weight Calculator for TMT Bars (D²/162)
Pick the bar diameter, enter the length per bar and how many bars. You get the total weight in kg and tonnes, weight per metre and per bar.
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Total steel weight
106.67kg
- Weight per length
- 0.889 kg/m
- Weight per bar
- 10.67 kg
- Total length
- 120 m
- In tonnes
- 0.107 t
Nominal weight. Real bars may differ by a few percent (IS 1786 rolling tolerance).
Show working
- 12² ÷ 162 = 0.8889 kg/m
- 0.8889 × 12 m × 10 = 106.67 kg
Weight chart
| Bar | kg per m | kg per 12 m bar |
|---|---|---|
| 6 mm | 0.22 | 2.67 |
| 8 mm | 0.4 | 4.74 |
| 10 mm | 0.62 | 7.41 |
| 12 mm | 0.89 | 10.67 |
| 16 mm | 1.58 | 18.96 |
| 20 mm | 2.47 | 29.63 |
| 25 mm | 3.86 | 46.3 |
| 28 mm | 4.84 | 58.07 |
| 32 mm | 6.32 | 75.85 |
How to use
- Choose the bar diameter (8, 10, 12, 16 mm and so on).
- Enter the length of one bar (a standard bar is 12 m / about 40 ft).
- Enter the number of bars to see total kg and tonnes.
Good to know
Weight per metre = D² ÷ 162 kg, where D is the bar diameter in mm. It comes from steel density 7850 kg/m³: π/4 × D² × 7850 ÷ 10⁶ = D² ÷ 162.2. IS 1786 lists nominal mass as 0.00617 × D², the same thing.
Quick figures: 8 mm = 0.395 kg/m, 10 mm = 0.617, 12 mm = 0.889, 16 mm = 1.58, 20 mm = 2.47, 25 mm = 3.86, 32 mm = 6.32 kg/m. A 12 m bar of 12 mm weighs about 10.7 kg.
Actual bars can be up to a few percent lighter or heavier within IS 1786 rolling tolerances, so the weighbridge figure may differ slightly. Steel is usually priced per kg or per tonne; ask for the weight slip.
Questions
What is the weight of a 12 mm TMT bar?
0.889 kg per metre, so a 12 m bar weighs about 10.67 kg.
Why D²/162?
Area of a circle × steel density: π × D²/4 mm² × 7850 kg/m³ = D²/162.2 kg per metre.
How many 12 m bars of 8 mm make a tonne?
One bar is 0.395 × 12 = 4.74 kg, so about 211 bars per tonne.
Can I enter length in feet?
Yes. Switch to Feet; weight per foot is also shown.
Is this the same for all brands?
Nominal weight is the same; rolling tolerance allowed by IS 1786 lets real bars vary slightly.