TMT Bar Weight Chart (8mm–40mm) & Calculator
Weight of TMT bars in kg per metre, the weight of one 12 m bar, and how many bars make a tonne, for every size from 8 mm to 40 mm. Use the calculator to convert bars to tonnes, or tonnes to bars.
TMT bar weight calculator
Nominal weights. Opens the Pertonne chat with your order typed in; a free account is needed to submit the inquiry.
TMT bar weight chart
| Size | Weight (kg/m) | One 12 m bar (kg) | Bars per tonne | Forms we supply |
|---|---|---|---|---|
| 8 mm | 0.394 | 4.73 | ≈ 212 | Straight, Bend, Coil |
| 10 mm | 0.616 | 7.39 | ≈ 135 | Straight, Bend, Coil |
| 12 mm | 0.887 | 10.64 | ≈ 94 | Straight, Bend, Coil |
| 16 mm | 1.578 | 18.94 | ≈ 53 | Straight, Bend |
| 20 mm | 2.465 | 29.58 | ≈ 34 | Straight, Bend |
| 25 mm | 3.851 | 46.21 | ≈ 22 | Straight, Bend |
| 32 mm | 6.310 | 75.72 | ≈ 13 | Straight |
| 40 mm | 9.860 | 118.32 | ≈ 8 | Straight |
Nominal weights, the same for Tata Tiscon, JSW Neosteel, Jindal Panther and SAIL, and for every grade (Fe500, Fe500D, Fe550D, CRS). Bars per tonne is rounded and assumes 12 m bars.
How to calculate TMT bar weight
Weight (kg/m) ≈ D² ÷ 162
D is the bar diameter in mm. The 162 comes from the density of steel (7,850 kg/m³). Multiply by the length in metres for the weight of one bar. Example: 12 mm → 12 × 12 ÷ 162 = 0.889 kg/m, so a 12 m bar weighs about 10.67 kg. The chart above shows 0.887 kg/m, the figure in the brands' catalogue data; the small difference is rounding.
Weight by size
8mm TMT bar weight
A 8 mm TMT bar weighs 0.394 kg per metre, so one 12 m bar weighs 4.73 kg. One tonne has about 212 bars of 12 m.
10mm TMT bar weight
A 10 mm TMT bar weighs 0.616 kg per metre, so one 12 m bar weighs 7.39 kg. One tonne has about 135 bars of 12 m.
12mm TMT bar weight
A 12 mm TMT bar weighs 0.887 kg per metre, so one 12 m bar weighs 10.64 kg. One tonne has about 94 bars of 12 m.
16mm TMT bar weight
A 16 mm TMT bar weighs 1.578 kg per metre, so one 12 m bar weighs 18.94 kg. One tonne has about 53 bars of 12 m.
20mm TMT bar weight
A 20 mm TMT bar weighs 2.465 kg per metre, so one 12 m bar weighs 29.58 kg. One tonne has about 34 bars of 12 m.
25mm TMT bar weight
A 25 mm TMT bar weighs 3.851 kg per metre, so one 12 m bar weighs 46.21 kg. One tonne has about 22 bars of 12 m.
32mm TMT bar weight
A 32 mm TMT bar weighs 6.310 kg per metre, so one 12 m bar weighs 75.72 kg. One tonne has about 13 bars of 12 m.
40mm TMT bar weight
A 40 mm TMT bar weighs 9.860 kg per metre, so one 12 m bar weighs 118.32 kg. One tonne has about 8 bars of 12 m.
Questions
How many 12 mm rods are in 1 tonne?
About 94 bars of 12 m. One 12 mm bar weighs 10.64 kg (0.887 kg/m × 12 m), and 1,000 ÷ 10.64 ≈ 94.
Does the grade or brand change the weight?
No. Nominal weight depends only on the diameter, so a 12 mm Fe500D bar and a 12 mm Fe550D bar have the same nominal weight, whatever the brand.
Why can the actual weight differ from the chart?
Rolled bars vary slightly from the nominal weight, within the tolerance allowed by IS 1786. The mill test certificate and the weighbridge slip at delivery show the actual weight.
Are TMT bars sold by weight or by number of bars?
By weight. Quotes are per tonne (MT), so use the calculator to convert the number of bars in your drawing into tonnes. Brands publish their maximum prices per piece; see the TMT price list today.
Which sizes and forms can I order on Pertonne?
Straight bars from 8 mm to 40 mm, bend from 8 mm to 25 mm, and coil from 8 mm to 12 mm, in Tata Tiscon, JSW Neosteel, Jindal Panther and SAIL.
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