How to calculate Steel TMT weight
12 May 2021, By SteelPrice.Today
Calculating the weight of TMT rebar is straightforward with specifications given by IS1786 standard.For the calculation of commercial TMT rebars, you need following parameters,
Length of Rebar
Though the ISI document (IS1786) does not mention standard length of a TMT rebar, the industry practice is 40ft or 12m as a standard length. While calculating the full rod weight, identify its length. REMEMBER 40Feet = 12.192 meter. Do not assume 40ft is same as 12meter.
Rod Count in a bundle
TMT rods are usually bent and tied in bundles for the ease of handling. Though the following counts given are followed as an industrial practice, it is subject to human error as most companies follow manual bundling activity.
If you are trying to find a bundle weight on a weighing machine, ensure to check the number of rods manually. Rods are bundles to ensure it lies in the range of 50-80Kg, which can be handled by two manual labors.
Section Weight of TMT rebars per meter length as per IS1786 |
|||
|---|---|---|---|
| Rod Diameter | Minimum Section Weight | Nominal Section Weight | Maximum Section Weight |
| 4mm | 0.092 kg | 0.099 kg | 0.106 kg |
| 5mm | 0.143 kg | 0.154 kg | 0.165 kg |
| 6mm | 0.206 kg | 0.222 kg | 0.238 kg |
| 8mm | 0.367 kg | 0.395 kg | 0.423 kg |
| 10mm | 0.574 kg | 0.617 kg | 0.660 kg |
| 12mm | 0.844 kg | 0.888 kg | 0.932 kg |
| 16mm | 1.501 kg | 1.580 kg | 1.659 kg |
| 20mm | 2.396 kg | 2.470 kg | 2.544 kg |
| 25mm | 3.735 kg | 3.850 kg | 3.966 kg |
| 28mm | 4.685 kg | 4.830 kg | 4.975 kg |
| 32mm | 6.121 kg | 6.310 kg | 6.409 kg |
| 36mm | 7.750 kg | 7.990 kg | 8.230 kg |
| 40mm | 9.564 kg | 9.860 kg | 10.156 kg |
Single Rod Weight of TMT rebar per 40ft (12.192m) length as per IS1786 |
|||
|---|---|---|---|
| Rod Diameter | Minimum Rod Weight | Nominal Rod Weight | Maximum Rod Weight |
| 6mm | 2.52 kg | 2.71 kg | 2.90 kg |
| 8mm | 4.48 kg | 4.82 kg | 5.15 kg |
| 10mm | 7.00 kg | 7.52 kg | 8.05 kg |
| 12mm | 10.29 kg | 10.83 kg | 11.37 kg |
| 16mm | 18.30 kg | 19.26 kg | 20.23 kg |
| 20mm | 29.21 kg | 30.11 kg | 31.02 kg |
| 25mm | 45.53 kg | 46.94 kg | 48.35 kg |
| 32mm | 74.62 kg | 76.93 kg | 79.24 kg |
Bundle Weight of TMT rebars per 40ft (12.192m) length as per IS1786 |
||||
|---|---|---|---|---|
| Rod Diameter | No of pieces in a Bundle | Minimum Bundle Weight | Nominal Bundle Weight | Maximum Bundle Weight |
| 6mm | 20 | 50.3 kg | 54.1 kg | 57.9 kg |
| 8mm | 10 | 44.8 kg | 48.2 kg | 51.5 kg |
| 10mm | 7 | 48.9 kg | 52.7 kg | 56.3 kg |
| 12mm | 5 | 51.4 kg | 54.1 kg | 56.8 kg |
| 16mm | 3 | 54.9 kg | 57.8 kg | 60.7 kg |
| 20mm | 2 | 58.4 kg | 60.2 kg | 62.0 kg |
| 25mm | 1 | 45.5 kg | 46.9 kg | 48.3 kg |
| 32mm | 1 | 74.6 kg | 76.9 kg | 79.2 kg |
Frequently asked Question on TMT weight
Does the weight vary based on TMT Grade?
No. TMT rods are available in various grades like Fe500, Fe500D, Fe550D, Fe600 etc. and they do not vary in Sectional weight. Hence do not assume that stronger TMT rods have higher section weight.
How the minimum & Maximum weights are calculated?
IS 1786 has given the tolerance range that needs to be followed for section weight of TMT rebars as follows
- 8mm and 10mm: ± 7%
- 12mm to 16mm: ± 5%
- 20mm to 32mm: ± 3%
Is there any thumb rule formula to calculate TMT weight quickly?
Yes, following formula is used in industry practices while estimating the rod weights (approximately)
Single rod of 40ft(or 12.192 meters) = Diameter² x 0.075kg
where Diameter in mm
Example: weight of 40 ft of 10mm rod = 10*10*0.075 = 7.5kg
What is Light weight TMT?
Light weight TMT is manufactured with the weight near its Minimum value. It is dangerous to use Light weight TMT as they may not meet the ISI requirement.
Are the TMT manufacturer allowed to fix their own section weight?
No. Section weight of a TMT rebar should be within its Minimum & Maximum section weight mentioned by IS1786. However, Manufacturers, set their process control to produce TMT rods with section weight preferred by its largest customer base. They should still maintain the weight tolerance specified by IS1786.