When buying TMT bars, size and weight are two of the most important things to check.
TMT bars come in different diameters, such as 8mm, 10mm, 12mm, 16mm and larger sizes. Each size has a different weight per metre. The weight also changes when you compare different bar lengths.
So, how much does a 12mm TMT bar weigh?
What is the weight of a 16mm bar?
How many kilograms does a standard 12-metre TMT rod weigh?
This TMT bar weight chart gives you a simple reference for common TMT bar sizes from 8mm to 40mm.
TMT Bar Size and Weight Chart
The table below shows the weight range published by JR Metal for its TMT bars.
| TMT Bar Size | Weight Per Metre | Approx. Weight Per 12m Rod |
|---|---|---|
| 8mm | 0.386 – 0.402 kg | 4.638 – 4.827 kg |
| 10mm | 0.604 – 0.629 kg | 7.247 – 7.543 kg |
| 12mm | 0.870 – 0.905 kg | 10.435 – 10.861 kg |
| 16mm | 1.546 – 1.609 kg | 18.552 – 19.309 kg |
| 20mm | 2.416 – 2.514 kg | 28.987 – 30.170 kg |
| 25mm | 3.774 – 3.928 kg | 45.293 – 47.141 kg |
| 32mm | 6.184 – 6.436 kg | 74.207 – 77.236 kg |
| 36mm | 7.827 – 8.146 kg | 93.919 – 97.752 kg |
| 40mm | 9.662 – 10.057 kg | 115.949 – 120.682 kg |
Weight values above are based on the current weight parameters published by JR Metal. The standard rod length is 12 metres. Actual supplied weight can vary within the stated range.
What Does TMT Bar Size Mean?
TMT bar size refers to the diameter of the steel bar.
For example:
- 8mm means the bar has an approximate diameter of 8mm.
- 10mm means the bar has an approximate diameter of 10mm.
- 12mm means the bar has an approximate diameter of 12mm.
- 16mm means the bar has an approximate diameter of 16mm.
As the diameter increases, the amount of steel in the bar also increases.
Therefore, a 20mm bar weighs more per metre than a 12mm bar.
The size you need depends on the structural design of the project. A structural engineer should specify the required bar diameter and grade.
Why Does TMT Bar Weight Matter?
TMT bar weight matters for several reasons.
1. Material Estimation
Builders and contractors need to estimate how much steel a project requires.
The bar size and weight help them calculate the approximate quantity of steel.
2. Purchase Planning
Steel is commonly purchased based on weight.
Therefore, knowing the approximate weight of each bar helps with procurement and budgeting.
3. Transportation
The total weight of the steel affects transportation and handling.
Larger quantities also require better planning at the construction site.
4. Stock Management
Contractors can compare the quantity received with their purchase documents.
This makes stock management easier.
5. Project Costing
Steel forms a major part of the material cost in many construction projects.
A reliable weight reference helps contractors prepare better estimates.
TMT Bar Weight Per Metre
One of the easiest ways to compare TMT bars is by looking at their weight per metre.
For example:
- An 8mm TMT bar weighs around 0.386–0.402 kg per metre.
- A 12mm TMT bar weighs around 0.870–0.905 kg per metre.
- A 16mm TMT bar weighs around 1.546–1.609 kg per metre.
- A 20mm TMT bar weighs around 2.416–2.514 kg per metre.
- A 25mm TMT bar weighs around 3.774–3.928 kg per metre.
The weight increases as the bar diameter increases.
This makes the TMT bar weight per metre useful when calculating steel requirements for a project.
8mm TMT Bar Weight
8mm TMT bars are among the smaller reinforcement sizes.
According to JR Metal’s published weight parameters, an 8mm bar weighs approximately:
0.386–0.402 kg per metre
For a standard 12-metre rod, the approximate weight is:
4.638–4.827 kg
The actual application of an 8mm bar depends on the structural design.
10mm TMT Bar Weight
A 10mm TMT bar weighs approximately:
0.604–0.629 kg per metre
For a 12-metre rod, the approximate weight is:
7.247–7.543 kg
10mm bars are commonly used in reinforcement applications where the structural design calls for this diameter.
12mm TMT Bar Weight
12mm is one of the commonly referenced TMT bar sizes in construction.
JR Metal’s published weight range is:
0.870–0.905 kg per metre
For a 12-metre rod:
10.435–10.861 kg
If you are checking the 12mm TMT bar weight, always consider the actual product specification and supplied weight rather than relying only on a generic theoretical value.
16mm TMT Bar Weight
A 16mm TMT bar weighs approximately:
1.546–1.609 kg per metre
For a 12-metre rod:
18.552–19.309 kg
The required diameter should always come from the structural design.
20mm TMT Bar Weight
A 20mm TMT bar weighs approximately:
2.416–2.514 kg per metre
For a 12-metre rod:
28.987–30.170 kg
Because the diameter is larger, the weight per metre is also significantly higher than 12mm and 16mm bars.
25mm TMT Bar Weight
A 25mm TMT bar weighs approximately:
3.774–3.928 kg per metre
For a 12-metre rod:
45.293–47.141 kg
25mm bars are used when the structural design requires a larger reinforcement diameter.
32mm TMT Bar Weight
A 32mm TMT bar weighs approximately:
6.184–6.436 kg per metre
For a 12-metre rod:
74.207–77.236 kg
At this size, each individual rod is significantly heavier. Therefore, transportation, lifting and site handling require proper planning.
36mm TMT Bar Weight
36mm is one of the larger reinforcement sizes.
JR Metal publishes a weight range of:
7.827–8.146 kg per metre
For a 12-metre rod:
93.919–97.752 kg
JR Metal lists 36mm as a special size produced according to requirements.
40mm TMT Bar Weight
40mm TMT bars are among the largest sizes listed by JR Metal.
The published weight range is:
9.662–10.057 kg per metre
For a 12-metre rod:
115.949–120.682 kg
JR Metal lists 40mm as a special size manufactured based on project requirements.
How to Calculate TMT Bar Weight
You can calculate the approximate weight of a TMT bar using its diameter and length.
A commonly used theoretical formula is:
Weight per metre = D² / 162
Here:
D = diameter of the bar in millimetres
For example, for a 12mm bar:
12² ÷ 162
= 144 ÷ 162
≈ 0.89 kg per metre
For a 12-metre bar:
0.89 × 12
≈ 10.67 kg
This theoretical value provides a useful reference. However, actual supplied weights can vary within the manufacturer’s specified range.
For procurement, billing and stock verification, always refer to the manufacturer’s product specifications and applicable standards.
TMT Bar Weight Formula: Quick Reference
| Bar Diameter | Approx. Theoretical Weight Per Metre |
|---|---|
| 8mm | 0.395 kg |
| 10mm | 0.617 kg |
| 12mm | 0.889 kg |
| 16mm | 1.580 kg |
| 20mm | 2.469 kg |
| 25mm | 3.858 kg |
| 32mm | 6.321 kg |
| 36mm | 8.000 kg |
| 40mm | 9.877 kg |
The values above use the common D²/162 calculation and are approximate theoretical values.
They should not replace the manufacturer’s declared product weight.
What TMT Bar Size Should You Use?
This is an important question.
You should not choose a TMT bar size based only on its weight.
The required size depends on the structural design.
For example, a structural engineer may specify different diameters for:
- Columns
- Beams
- Slabs
- Footings
- Retaining walls
- Bridges
- Industrial structures
Each structural member carries different loads.
Therefore, the reinforcement requirement can also differ.
The simple rule is:
Don’t select the bar size yourself based on a weight chart.
Use the size and grade specified by the structural engineer.
The weight chart helps you calculate and verify quantities. It does not replace structural design.
Does a Bigger TMT Bar Mean Better Construction?
Not necessarily.
A larger bar weighs more and can carry different loads. However, that does not mean you should always choose the largest available size.
Structural reinforcement needs to match the design.
For example, using a larger bar where it is not required can affect:
- Reinforcement spacing
- Concrete placement
- Structural detailing
- Construction cost
- Bar bending and handling
Therefore, the correct bar is the one that meets the project’s design requirements.
TMT Bar Size vs Weight: What Should Buyers Check?
Before buying TMT bars, check these details:
1. Diameter
Confirm the required bar size.
2. Grade
Check the specified grade, such as Fe 500 or Fe 500D, based on the project design.
3. Length
Confirm whether the supplied bars are standard 12-metre lengths or customized lengths.
JR Metal states that its standard TMT bar length is 12 metres, while customized lengths can be supplied up to 22 metres.
4. Weight
Compare the supplied weight with the manufacturer’s declared range.
5. Quality Documentation
Check the relevant test certificates and product documentation.
6. Manufacturer
Choose a manufacturer that maintains consistent production and quality control.
JR Metal states that it uses in-house testing, spectrometer analysis and Universal Testing Machines as part of its production quality process.
How Many TMT Bars Are in One Tonne?
The answer depends on the bar diameter.
A smaller bar weighs less. Therefore, you get more individual bars per tonne.
A larger bar weighs more. As a result, you get fewer bars per tonne.
For an approximate calculation:
Number of bars = Total steel weight ÷ Weight of one bar
For example, if one 12-metre bar weighs approximately 10.67 kg:
1,000 ÷ 10.67 ≈ 93.7 bars
So, one tonne would contain roughly 94 theoretical 12mm bars at that reference weight.
The actual number can vary because the supplied bar weight may fall within the manufacturer’s specified range.
TMT Bar Weight Chart: Quick Summary
If you only need a quick reference, use this table:
| Size | Approx. Weight / Metre | Approx. Weight / 12m Rod |
|---|---|---|
| 8mm | 0.386–0.402 kg | 4.638–4.827 kg |
| 10mm | 0.604–0.629 kg | 7.247–7.543 kg |
| 12mm | 0.870–0.905 kg | 10.435–10.861 kg |
| 16mm | 1.546–1.609 kg | 18.552–19.309 kg |
| 20mm | 2.416–2.514 kg | 28.987–30.170 kg |
| 25mm | 3.774–3.928 kg | 45.293–47.141 kg |
| 32mm | 6.184–6.436 kg | 74.207–77.236 kg |
| 36mm | 7.827–8.146 kg | 93.919–97.752 kg |
| 40mm | 9.662–10.057 kg | 115.949–120.682 kg |
These are JR Metal’s currently published weight ranges.
Frequently Asked Questions
What is the weight of an 8mm TMT bar?
A 12-metre 8mm TMT bar weighs approximately 4.638–4.827 kg, based on JR Metal’s published weight parameters.
What is the weight of a 10mm TMT bar?
A 12-metre 10mm TMT bar weighs approximately 7.247–7.543 kg.
What is the weight of a 12mm TMT bar?
A 12-metre 12mm TMT bar weighs approximately 10.435–10.861 kg.
What is the weight of a 16mm TMT bar?
A 12-metre 16mm TMT bar weighs approximately 18.552–19.309 kg.
What is the weight of a 20mm TMT bar?
A 12-metre 20mm TMT bar weighs approximately 28.987–30.170 kg.
What is the weight of a 25mm TMT bar?
A 12-metre 25mm TMT bar weighs approximately 45.293–47.141 kg.
What is the weight of a 32mm TMT bar?
A 12-metre 32mm TMT bar weighs approximately 74.207–77.236 kg.
What is the weight of a 36mm TMT bar?
A 12-metre 36mm TMT bar weighs approximately 93.919–97.752 kg.
What is the weight of a 40mm TMT bar?
A 12-metre 40mm TMT bar weighs approximately 115.949–120.682 kg.
What is the formula for TMT bar weight?
A commonly used theoretical formula is:
Weight per metre = D² / 162
Here, D represents the bar diameter in millimetres.
Is TMT bar weight the same for every manufacturer?
Not necessarily.
Actual supplied weight can vary within the applicable manufacturing and product specifications. Therefore, buyers should check the manufacturer’s declared weight parameters and relevant quality documentation.
What is the standard TMT bar length?
JR Metal lists 12 metres as its standard TMT bar length. It also states that customized lengths can be supplied up to 22 metres, while 36mm and 40mm are available as special sizes depending on requirements.
Final Takeaway
Understanding TMT bar size and weight makes steel estimation easier.
The basic relationship is simple:
Larger diameter = Higher weight per metre
However, weight is only one part of choosing reinforcement steel.
The correct TMT bar size and grade should always follow the structural design and project requirements.
For procurement, contractors and buyers should also check the bar diameter, length, declared weight, grade, test documentation and manufacturer quality standards.
JR Metal manufactures TMT bars in sizes from 8mm to 32mm, with 36mm and 40mm special sizes available based on requirements. The company also states that its standard bar length is 12 metres, with customized lengths available.
If you are looking for TMT bars for residential, commercial or infrastructure projects, contact JR Metal to discuss your project requirements and steel quantity needs.
