TMT Bar Size Chart 2026: 4 Soot to 25mm - Weight, Uses and Buying Guide
Walk into any steel market in India and you will hear two languages spoken at the same time. The dealer quotes sizes in millimetres - 8 mm, 12 mm, 16 mm - while your contractor asks for "2 soot" and "4 soot" sariya without ever opening a scale. A single wrong translation between these two systems, or a bundle picked without checking its weight, can quietly cost you 8 to 10 percent of your steel budget. This TMT bar size chart 2026 gives you every standard diameter from 6 mm to 32 mm, its soot name, weight per metre and per 12 m piece, approximate bundle count, and exactly where each size should be used in your house - slab, beam, column and footing.
Quick Answer: Complete TMT Bar Size Chart at a Glance
Here is the complete chart first, so you can screenshot it and take it to the site. Weight per metre uses the standard formula d x d / 162 (d in mm), and piece weight assumes the standard 12 m delivery length.
| Size (mm) | Soot Name | Weight per Metre (kg) | 12 m Piece Weight (kg) | Approx Pieces per 100 kg Bundle | Most Common Use |
|---|---|---|---|---|---|
| 6 mm | 1.5 soot | 0.222 | 2.66 | 37-38 | Stirrups, distribution bars, slab mesh |
| 8 mm | 2 soot | 0.395 | 4.74 | 21 | Slab main and distribution steel, stirrups |
| 10 mm | 2.5 soot | 0.617 | 7.40 | 13-14 | Slab in longer spans, small beams, columns in G+0 |
| 12 mm | 3 soot | 0.888 | 10.66 | 9 | Beams, columns, footing mesh |
| 16 mm | 4 soot | 1.580 | 18.96 | 5 | Columns, primary beam bars, footings |
| 20 mm | 5 soot | 2.469 | 29.63 | 3-4 | Columns in G+2 and above, large footings |
| 25 mm | 6 soot | 3.858 | 46.30 | 2 | Raft footings, pile caps, commercial frames |
| 32 mm | 8 soot | 6.313 | 75.76 | 1 | Heavy structural work, rarely used in homes |
Bundle weights vary by plant (many mills pack 100 kg, others pack by piece count), so always confirm the bundle weight written on the tag before you count bundles. Our detailed TMT weight chart covers per-piece and per-metre weights for every grade if you need the full calculation sheet.
What Does "Soot" Mean in Sariya Sizes?
Soot (also spelled sut or sooti) is a contractor slang still alive in Uttar Pradesh, Bihar, Jharkhand, Madhya Pradesh and parts of Rajasthan, while Maharashtra, Gujarat and the south quote everything in millimetres. The working rule used in most markets is 1 soot = 4 mm of diameter, which gives you the conversions in the chart above: 2 soot is your 8 mm bar, 3 soot is 12 mm, 4 soot is 16 mm and 5 soot is 20 mm.
Two honest cautions before you rely on this:
- Regional drift is real. Some localities use soot loosely, and older mild-steel habits map soot to slightly different sizes. Whenever size matters structurally, repeat the order back in millimetres and get the invoice to show millimetres too.
- Price always follows weight, not soot. Whether you call it 4 soot or 16 mm, the dealer bills per kilogram. Knowing the piece weight from the chart protects you when the bundle is short.
Standard TMT Bar Sizes Available in India in 2026
IS 1786 TMT bars are rolled in diameters from 6 mm to 50 mm, but the retail market in India effectively stocks eight sizes. Everything smaller than 6 mm is sold as wire or welded mesh, and anything above 25 mm is rarely seen in residential work except rafts and pile caps in soft-soil zones.
- 6 mm and 8 mm - the workhorse sizes for slab mesh, distribution steel and stirrups (the vertical rings inside columns and beams).
- 10 mm and 12 mm - beams, smaller columns and footing mesh in single-storey houses.
- 16 mm and 20 mm - the primary column and beam bars in G+1 to G+3 houses.
- 25 mm and 32 mm - raft footings, pile caps and commercial frames; most homeowners never buy these.
Bars are delivered in the standard 12 m length, and a few mills also supply 9 m. Cutting charges and wastage change with length, so confirm the length on the invoice: a 9 m piece of 16 mm weighs about 14.2 kg, not 18.96 kg.
Which TMT Bar Size to Use Where in a House
The exact size always comes from your structural drawing and engineer, but the table below shows the pattern you will see in 9 out of 10 Indian homes in 2026.
| Structural Member | Typical Main Bars | Typical Distribution / Stirrups | Notes |
|---|---|---|---|
| Roof slab (100-125 mm) | 8 mm or 10 mm | 6 mm or 8 mm | 10 mm when spans cross 4 m |
| Staircase waist slab | 10 mm | 8 mm | Plus 12 mm at landing support zones |
| Beams (lintel, roof) | 12 mm or 16 mm | 8 mm stirrups | 16 mm for spans over 4.5 m |
| Columns, G+0 to G+1 | 12 mm or 16 mm | 8 mm stirrups at 150 mm | Minimum 4 bars, corners mandatory |
| Columns, G+2 and above | 16 mm or 20 mm | 8 mm or 10 mm stirrups | Closer stirrups near joints per engineer |
| Isolated footings | 12 mm or 16 mm | Same mesh both ways | Size grows with soil load and plot load |
| Raft footing | 16 mm to 25 mm | As per drawing | Soft soil, high water table zones |
For a whole-house quantity instead of member-by-member sizes, read our guide on how to calculate total sariya required for a 1000 sq ft house, which adds up all these members into tonnes and bundles.
How to Calculate Bar Weight from the Size Chart
The one formula that runs the entire Indian steel market is the unit weight rule:
Weight per metre (kg) = d x d / 162, where d is the bar diameter in millimetres.
Worked example for a 16 mm bar: 16 x 16 = 256, divided by 162 = 1.58 kg per metre. One 12 m piece therefore weighs 1.58 x 12 = 18.96 kg, and a 5-piece bundle is just under 95 kg. The same math for 12 mm gives 0.888 kg/m and 10.66 kg per piece - which is why the 12 mm bundle is the most common unit of counting at sites.
Why 162? It folds the density of steel (7850 kg/cu m) and the circle area formula into one divisor. You never need to re-derive it; you only need it to audit weights, which is exactly where most steel losses hide.
Bundle Weights, Piece Counts and How Steel Is Sold
Three facts about buying by bundle will save you arguments at the godown:
- Bundle weight is not fixed nationally. A bundle of 12 mm x 12 m bars commonly weighs 100 to 130 kg depending on the mill and the number of pieces packed (typically 9 to 12 pieces). Read the tag, do not assume.
- Count, then weigh, then pay. Where a weighbridge is unavailable, the standard audit is: number of pieces x piece weight from the chart, then compare against the bundle weight on the tag. A gap of more than 3 to 4 percent deserves a conversation before unloading.
- Short-length rods are cheaper and riskier. Some dealers discount 6 m or 9 m rods. Fine for stirrups, but each cut in a continuous beam bar is a lap splice that eats steel and needs engineer approval.
Grade and size are two different choices. Sizes are covered here; for the Fe415 versus Fe500 versus Fe500D decision and the rib-pattern checks that expose duplicate rolling, see our complete sariya buyer's guide covering types, grades and sizes.
IS 1786 Grades and What the Size Chart Does Not Tell You
The size chart tells you the diameter; IS 1786 tells you the strength. The 2026 market sells four common grades in the same sizes:
- Fe415 - the old minimum, still available, declining use.
- Fe500 - the current default for house frames.
- Fe500D - the D stands for ductility (6 percent or higher elongation); the right choice in seismic zones III to V and almost every city today.
- Fe550D - premium brands, allows slightly leaner sections; check your engineer's comfort level before substituting.
A 16 mm Fe415 bar and a 16 mm Fe500D bar look identical on the size chart but are not interchangeable on the drawing. The rib pattern, brand mark and grade mark embossed on every metre of genuine TMT are your field proof - photograph the ribs before unloading.
Five Common Mistakes When Buying TMT by Size
- Ordering by soot over the phone. Regional drift means "3 soot" is 12 mm in one market and 10 mm in another. Confirm millimetres on paper.
- Assuming every bundle weighs 100 kg. Bundle weights range 80 to 130 kg across mills; your total tonne count changes with the tag, not with your assumption.
- Buying 8 mm as "half of 16 mm". An 8 mm bar is not half an 16 mm bar in strength - load capacity scales with the square of the diameter, which is exactly why the d x d / 162 formula exists.
- Accepting underweight rods. IS 1786 allows a small negative tolerance on diameter (typically 0.3 mm on 12 mm and 0.4 mm on 16 mm). A cheap local bar at full negative tolerance can weigh 5 to 7 percent under the chart value. One vernier caliper check per bundle catches this.
- Mixing grades in one member. Never lap an Fe415 bar into an Fe500D column; the lap length assumptions differ and the joint becomes the weak point.
How to Verify Size and Weight at the Site in 10 Minutes
You need three tools and no engineering degree:
- Vernier caliper: measure the rib-to-rib diameter across 3 random bars per size. 12 mm should read 11.7 mm or better; 16 mm should read 15.6 mm or better.
- Spring scale or bathroom-scale hack: weigh one full 12 m piece against the chart value (10.66 kg for 12 mm, 18.96 kg for 16 mm). Under 95 percent of chart weight on multiple pieces means you are paying for air.
- Photo of ribs and grade mark: genuine TMT carries a repeating brand and grade embossing. Absent or irregular ribs point to duplicate rolling - reject the lot and ask for the mill test certificate against the bundle tag number.
Frequently Asked Questions
What is the standard size of TMT bars for house construction?
Most Indian homes use 8 mm and 10 mm in slabs, 12 mm and 16 mm in beams and columns, and 12 mm to 20 mm in footings. 6 mm is reserved for stirrups and distribution steel, and 25 mm and above appear only in rafts and commercial frames.
How do I convert sariya size from soot to mm?
The market rule is 1 soot = 4 mm: 2 soot is 8 mm, 3 soot is 12 mm, 4 soot is 16 mm and 5 soot is 20 mm. Because the slang drifts by region, always confirm the millimetre size on the invoice.
What is the weight of a 12 mm TMT bar per piece?
A 12 mm TMT bar weighs 0.888 kg per metre using d x d / 162, so one standard 12 m piece weighs about 10.66 kg and a 12 m long bundle of 9 to 12 pieces weighs roughly 96 to 128 kg depending on packing.
Which is stronger, 4 soot or 16 mm sariya?
They are the same bar - 4 soot is the local name for the 16 mm diameter in most markets. Strength within the same diameter depends on the grade (Fe500 or Fe500D), not on the slang used to order it.
How many TMT bars are in one bundle?
There is no national standard: bundles range from about 37 pieces for 6 mm to 2 pieces for 25 mm at a nominal 100 kg, and many mills pack by fixed piece counts instead. The bundle tag weight is the only number that should go into your calculation.
Final Word
Carry this chart to the market and you stop being the customer who "trusts the dealer's bundle". The three numbers worth memorising are 1 soot = 4 mm, the unit-weight formula d x d / 162, and your own design's member sizes from the structural drawing. Weigh one piece per bundle against the chart, verify the grade mark on the ribs, and insist that every invoice reads in millimetres and kilograms - that single habit closes the two biggest leakages in Indian home building, underweight rods and mis-sold sizes, and typically protects 5 to 8 percent of your total steel spend.
