Construction is not an easy task. The most important part of any construction is a solid base. The base decides the strength and the durability of any concretized structure. TMT bars form the base of structures to ensure that they stand tall for years to come. There are different TMT bars, lengths and weight, and they are used in different types of structures. Small houses to big industries, TMT bars provide a robust establishment for all.

What are TMT Bars?

TMT Bars is an acronym for Thermo-Mechanically Treated Bars. These are the thin bars that are used during construction for giving strength and stability to any concrete structure.

TMT bars have a rigid exterior and a flexible interior. This combination makes TMT bars bendable as well as durable. The different length and weight of TMT bars offer the perfect support for any building structure.

What is the Process of Making TMT Bars?

The process of making TMT bars involves several steps. First, the melting of steel. The molten steel is then rapidly cooled down by pouring water at different intervals. These intervals of pouring water on the molten steel bars determine the grade and quality of the TMT bars. These bars thus come in different grades ranging from Fe415 to Fe600, where Fe refers to the per square millimetre stress of yield in Newton. These grades define the usage of TMT bars. Lower-grade bars are best for small-scale domestic constructions, and higher-grade bars are best for large-scale industrial constructions.

The next step in the creation of TMT bars is layering. TMT bars are layered wit an exterior coating to ensure that they can sustain different conditions. It is this property of the TMT bars that makes them rust-free, earthquake resistant, and durable throughout the trials of years.

What are the Different TMT Bars’ Length and Weight?

TMT bars can exist in different lengths and weights. Different brands can produce TMT bars in different sizes. Most brands make TMT bars that are 12 meters or 40 feet in length.

We have prepared a table in order to understand better and illustrate the relation between the different TMT bars length and weight.


Size of TMT Bar (in millimeter) Number of TMT rods per bundle Weight of TMT rods per bundle

(in kilograms)

8 10 47
10 7 52
12 5 53
16 3 57
20 2 59
25 1 46
32 1 76


Usually, when contractors, builders, architects, and house owners buy or order TMT bars, they do so in terms of the size of the TMT bars, the weight of TMT bars, the number of TMT bars bundles, and the number of TMT bars per bundle.

The size of a TMT bar is defined by its diameter in millimeter (mm). TMT bars exist in 7 size variations- 8 millimeters, 10 millimeters, 12 millimeters, 16 millimeters, 20 millimeters, 25 millimeters, and 32 millimeters.

The weight of a TMT bar is calculated based on the following formula:

(dia * dia) / 162) * 12 = approximate weight of one TMT bar in kilograms

With the use of this formula, we can get the approximate weight of a single TMT bar from different sizes. One TMT steel bar respectively sized 8 mm in diameter weighs approximately 4.74 kilograms, 10 mm in diameter weighs 7.4 kg, 12 mm in diameter weighs 10.6 kg, 16 mm in diameter in diameter weighs 18.6 kg, 20 mm in diameter weighs 29.6 kg, 25 millimeters in diameter weighs 46.2 kg, and 32 millimeters in diameter weighs 75.8 kg.

As per content, there are different numbers of rod in a bundle for different sizes of TMT bars. One bundle of TMT bars sized 8 mm in diameter contains 10 rods. One bundle of TMT bars sized 10 mm in diameter contains 7 rods. One bundle of TMT bars sized 12 mm in diameter contains 5 rods. One bundle of TMT bars sized 16 mm in diameter contains 3 rods. One bundle of TMT bars sized 20 mm in diameter contains 2 rods. One bundle of TMT bars sized 25 or 35 mm in diameter contain 1 rod each.

Based on the number of rods in each bundle, the bundle of differently sized TMT rods weighs different. One bundle of 8 mm sized TMT steel bar weighs 47 kilograms. One bundle of 10 mm sized TMT steel bar weighs 52 kilograms. One bundle of 12 mm sized TMT steel bar weighs 53 kilograms. One bundle of 16 mm sized TMT steel bar weighs 57 kilograms. One bundle of 20 mm sized TMT steel bar weighs 59 kilograms. One bundle of 25 mm sized TMT steel bar weighs 46 kilograms. One bundle of 32 mm sized TMT steel bar weighs 76 kilograms.

As per ISI standards, weight tolerance of each TMT bar can be calculated by following a particular formula. We can get an approximate bracket of weight tolerance for the differently sized bar based on this formula. The weight tolerance of 8 mm to 10 mm bars can be gauged by adding or subtracting 7% from its weight, of 12 mm to 16 mm by adding or subtracting 5%, and of 20 mm to 32 mm by adding or subtracting 3%. What this means is that an 8mm bundle may weigh anywhere between 44 and 51 kg, and it will still be considered safe and usable.

There are different TMT bar lengths and weights. Choosing the right TMT bars based on your preference can make any construction easy, strong, as well as affordable. Keep in mind the grade, durability, flexibility, uniformity, brand, and quality of the TMT bar while finalizing your purchase.

Once built, any construction stays, or is at least supposed to stay, for long. To ensure that your first steps to building the construction of your dream are taken in the right direction, it is imperative to find all the right construction materials. Research and review the different TMT bar lengths and weights and build yourself a perfect and stable construction.