Why TMT bar sizes and weights matter before you order
The rule of thumb is simple: weight in kg per metre is roughly the diameter squared, divided by 162. A 12 mm bar comes out at about 0.89 kg/m, and a 25 mm bar at about 3.86 kg/m.
That formula is also why a 32 mm bar costs far more than twice a 16 mm bar. It carries four times the steel.
- Structural safety. Stirrups and distribution steel use 8 to 10 mm. Beams, columns and slabs use 12 to 16 mm. Heavy rafts need 20 to 32 mm. Too small can compromise the structure; too big wastes money.
- Site logistics. Bar length and bundle weight decide your truck count and crane lifts. A site that plans around the real weight of a bar runs smoother.
TMT bar grades explained: Fe 500, Fe 550, Fe 550D
The number in a grade is the minimum yield strength in N/mm². A higher grade gives more strength from the same section. Ductility, how far a bar stretches before it breaks, matters just as much in seismic zones.
| Grade | Yield min | Elongation min | UTS/YS | Typical use |
|---|---|---|---|---|
| Fe 500 | 500 N/mm² | 12% | ≥ 1.08 | Homes, commercial buildings, slabs, beams, columns |
| Fe 550 | 550 N/mm² | 10% | ≥ 1.06 | Heavy-load structures, industrial sheds |
| Fe 550D | 550 N/mm² | 14.5% | ≥ 1.08 | Infrastructure, high-rise, seismic zones |
We make all three to IS 1786:2008. Fe 550D has the same yield strength as Fe 550 but more elongation, 14.5% against 10%. It is the grade engineers reach for on earthquake-resistant designs. For most homes, Fe 500 is the right pick.
Every bar is rolled on German TEMPCORE lines: a water-quenched hard surface over a soft, bendable core. Strong enough to grip the concrete, flexible enough to bend without snapping.
TMT bar sizes and weight chart
We make seven standard sizes, all in 12 m lengths. Weights are the nominal mass from IS 1786 Table 1.
| Size | kg per metre | kg per 12 m bar | Bars per tonne | Typical use |
|---|---|---|---|---|
| 8 mm | 0.395 | 4.74 | ~211 | Stirrups, distribution steel |
| 10 mm | 0.617 | 7.40 | ~135 | Distribution steel, light residential |
| 12 mm | 0.888 | 10.66 | ~94 | Beams, columns, slabs |
| 16 mm | 1.580 | 18.96 | ~53 | Beams, columns, slabs |
| 20 mm | 2.470 | 29.64 | ~34 | Heavy columns, rafts |
| 25 mm | 3.850 | 46.20 | ~22 | Heavy columns, industrial |
| 32 mm | 6.310 | 75.72 | ~13 | Bridges, flyovers, infrastructure |
Small bars are the lightest and cheapest, and you use plenty of them. The big bars carry several times the steel per metre, so the cost concentrates there. If your schedule is mostly 12 and 16 mm, you are in the common range for residential and commercial work.
Send us your bar bending schedule and we will price it by size and weight within one business day.
What steel supply services RD TMT provides
- Bulk supply.
Consistent tonnage on a schedule for builders, contractors and RMC-linked projects. See bulk TMT bar supply.
- Bar bending schedule pricing.
Send your schedule and it is priced by size and weight, so the steel cost is known before you commit.
- Dealer and stockist support.
Reliable stock for retailers across Karnataka. See dealers and stockists.
- Grade-specific supply.
When a drawing calls for Fe 550D or a particular size mix, we supply to that specification.
- A test certificate with every load.
From our NABL accredited lab, showing the batch chemistry and strength, traced to its heat number.
- Phased delivery.
Bulk and infrastructure orders staged around your pour schedule. See TMT steel delivery.
- NABL lab accreditation
- NABLT0826KA18884
- BIS licence, IS 1786
- CM/L-6200193709
- On every dispatch
- Heat number to test certificate
Local supply: where RD TMT delivers around Bengaluru
Our plant is at Somanahalli Industrial Area, Maddur Taluk, Mandya, on the Bengaluru–Mysuru corridor, about 80 km from Bengaluru. The expressway runs past the works, which keeps logistics lean and delivery windows predictable.
From there we deliver to Peenya, Nelamangala, Bidadi, Harohalli, Bommasandra and the HSR–Sarjapur belt, and to sites across Mandya, Mysuru and the wider state. Beyond Karnataka we supply Tamil Nadu and Andhra Pradesh, with pan-India delivery for large projects.
How to choose the right TMT bar
- Match the grade to the structure. Most residential work never needs more than Fe 500. Fe 550D matters for seismic or high-rise builds.
- Confirm the standard. Ask for bars made to IS 1786:2008.
- Check the marking and ribs. Genuine TMT bars carry the ISI mark and the maker’s name, with an even rib pattern.
- Check elongation as well as strength. A strong but brittle bar is a liability.
- Check the source. A local manufacturer with a plant you can visit is easier to hold to account than a reseller.
- Plan delivery into your schedule. Late steel delays a pour, whatever its quality.
Frequently asked questions
Which TMT bar grades does RD TMT make?
Fe 500, Fe 550 and Fe 550D, all to IS 1786:2008. Fe 550D has higher elongation and tighter chemistry, which is what engineers ask for in earthquake-resistant design.
Which sizes are available?
8, 10, 12, 16, 20, 25 and 32 mm TMT bars in 12 m lengths. MS billets in 100, 110, 125 and 150 mm square sections.
How do I work out the weight of a TMT bar?
Weight in kg per metre is roughly the diameter squared divided by 162. A 12 mm bar is about 0.89 kg/m, or about 10.66 kg per 12 m bar.
What is the difference between Fe 550 and Fe 550D?
Both have a minimum yield strength of 550 N/mm². The D stands for ductility: Fe 550D has 14.5% elongation against 10%, which suits seismic zones and structures that must bend without breaking.
Are your TMT bars made to IS 1786:2008?
Yes. Our bars are made to IS 1786:2008, and every consignment is checked before dispatch.
Do you give a test certificate with every load?
Yes. Every lorry leaves with a test certificate from our NABL accredited lab, showing the chemistry and strength of that batch, traced to its heat number.
Is RD TMT approved for government projects?
Yes. Tamil Nadu PWD, Karnataka Power Corporation, the Bangalore Development Authority, Chennai Metro Rail and Karnataka PWD have approved our bars. KRIDL, DRDA Madurai and AP State Housing Corporation have bought them through tender.
Where do you deliver TMT bars?
Across Karnataka, Tamil Nadu and Andhra Pradesh from our plant in Mandya, near Bengaluru and Mysuru. Pan-India delivery for large projects.
Can you price my bar bending schedule?
Yes. Send it over and it will be priced by size and weight within one business day.