eGigFree Steel Weight Calculator: TMT Bars in kg
Work out the weight of TMT bars by diameter and length with the D²/162 rule, and the weight of steel plates.
Weight of TMT and other steel bars by the standard site rule, D² ÷ 162 kg per metre. Use it for estimates: your supplier’s weighbridge slip decides what you pay for.
Bars
Number of bars of each size:
Total steel weight
0 kg
In tonnes
Cost at your rate
Steel plate or sheet
Plate weight
0 kg
Length × width × thickness × 7,850 kg per m³.
The steel weight formula
Weight in kg per metre = D² ÷ 162, where D is the bar diameter in mm. It comes from steel’s density of 7,850 kg per m³, which gives 0.00617 × D².
Example: 10 bars of 12 mm, each 12 m long: 12 × 12 ÷ 162 = 0.889 kg per metre. Total length 120 m, so about 107 kg.
| Diameter | kg per metre | kg for a 12 m bar |
|---|---|---|
| 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 |
Questions people ask
What is the formula for steel weight?
For a round bar, weight in kg per metre = D² ÷ 162, where D is the diameter in mm. A 16 mm bar weighs about 1.58 kg per metre.
Why is 162 used?
Steel weighs about 7,850 kg per m³. Working out the area of a circle in mm and multiplying by that density gives 0.00617 × D², and 1 ÷ 0.00617 is about 162.
How long is one TMT bar?
TMT bars are usually supplied about 12 metres long, which is the default here. Check with your supplier.
Why does the weight on my bill differ?
Bars are rolled within allowed tolerances, so the real weight can differ a little from this figure. Suppliers often bill by the weighed total, so ask for the weighbridge slip.
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