How TMT bars are actually traded
Every TMT deal carries four identifiers: brand, grade, size and weight. You need all four to quote a rate, pick the right bundle at the yard and settle the bill without an argument.
Brand
IS 1786 requires bars to carry rolled-in marks showing the manufacturer or brand name. The BIS product manual asks for the mark at intervals of no more than 3 metres.
Grade
IS 1786:2008, as amended, covers Fe 415, Fe 415D, Fe 415S, Fe 500, Fe 500D, Fe 500S, Fe 550, Fe 550D, Fe 600, Fe 650 and Fe 700. The number is the specified minimum 0.2% proof stress or yield stress in N/mm². D and S mark categories with additional requirements.
Size
IS 1786:2008, as amended, lists nominal sizes from 4 mm to 50 mm, with other sizes by mutual agreement. Trade bars are commonly supplied in 12 m lengths. Each bundle carries a tag showing its cast or lot number, grade and size.
Weight
Suppliers quote rates per kg or per tonne and bill on the actual weighbridge weight. Site teams, meanwhile, count bars by diameter and length. The number of bars in a bundle varies by manufacturer.
So a single line on a TMT order reads something like "Brand X, Fe 500D, 12 mm, 5 tonnes". The customer may think of it as "about 470 bars". It gets loaded as bundles, and it gets billed on whatever the weighbridge slip says. If your system stores only one of those numbers, somebody has to reconcile the rest by hand.
Chart weight versus actual weight
IS 1786:2008 fixes a nominal mass per metre for each size, taking steel density as 0.00785 kg per mm² of cross-section per metre. It then allows a tolerance on that mass. That tolerance is why 100 bars of 12 mm rarely weigh exactly what the chart says, and why the actual loaded weight matters for billing.
| Nominal size | Mass per metre (kg) | One 12 m bar (kg) | 12 m bars per tonne | Batch tolerance |
|---|---|---|---|---|
| 8 mm | 0.395 | 4.74 | 211.0 | ±7% |
| 10 mm | 0.617 | 7.40 | 135.1 | ±7% |
| 12 mm | 0.888 | 10.66 | 93.8 | ±5% |
| 16 mm | 1.580 | 18.96 | 52.7 | ±5% |
| 20 mm | 2.470 | 29.64 | 33.7 | ±3% |
| 25 mm | 3.850 | 46.20 | 21.6 | ±3% |
| 28 mm | 4.830 | 57.96 | 17.3 | ±3% |
| 32 mm | 6.310 | 75.72 | 13.2 | ±3% |
Mass per metre and batch tolerance are from IS 1786:2008, Table 1 and Table 2. The same standard allows an individual sample to be up to 8% light (up to 10 mm), 6% light (over 10 up to 16 mm) or 4% light (over 16 mm). The 12 m bar weight and bars per tonne are simple arithmetic on the nominal mass. They are theoretical figures, not a supplier's actual count. For every size, see the TMT bar weight chart. For other sections, use the steel weight calculator.
Here's what that means in practice. Take 100 bars of 12 mm at 12 m each. On paper that's 1,065.6 kg. At the edges of the ±5% batch tolerance, the same 100 bars could weigh anything from about 1,012 kg to about 1,119 kg. Across a full truck, that difference is real money, and it's the reason TMT is billed on the actual weight, not on the bar count.
Quick estimate: bars to tonnes
Uses the IS 1786:2008 nominal mass per metre and batch tolerance. It's only an estimate. Your bill should use the weighed figure.
How a TMT order runs in SteelERP
- Inquiry to order. Log the rate inquiry when a builder or retailer calls, then convert it into an order once the rate is agreed. You don't have to type it in twice.
- Brand, grade and size on the line. Each item comes from your product and size catalogue, with its HSN code attached. Set up each brand and grade you deal in as a product and its diameters as sizes, so "Fe 500D 16 mm" from one mill never gets mixed up with another's.
- Ordered weight, then actual weight. Each item records the weight ordered and, at dispatch, the actual loaded weight from your weighbridge slip. The bill is raised on the actual weight.
- Deliver in parts, in the unit the yard uses. Split an order into delivery sub-orders counted in kg, metres or pieces. Each sub-order has its own loading, challan and delivery status. SteelERP handles the tonnage conversion.
- GST, challan and Tally. CGST, SGST or IGST is calculated on the order line with the HSN code. The challan PDF can go to the customer on WhatsApp from your own WhatsApp Business account, and Tally Prime picks up printed challans through the integration.
Buying, stock and planning for TMT
When one purchase order arrives in more than one truck, SteelERP lets that purchase order carry multiple purchase advices, and goods are received against each advice. You always know how much of the order has actually come in.
Actual-weight billing
Ordered and actual loaded weight on every item, billing on the actual, with tonnage conversions.
Delivery sub-orders
Dispatch by kg, metre or piece. Each part has its own loading, challan and status.
Purchase advices
Multiple purchase advices per purchase order, with goods receipt per advice.
Multi-yard stock
Stock by warehouse, with users scoped to their own yard, plus low-stock reporting size by size.
Forecast and reorder
Advisory demand forecast, anomaly detection and reorder suggestions. They're suggestions only, so you make the call.
GST, TCS and 50+ reports
GST on the order line with HSN, plus GST summary, TCS and discount reports, and a weekly PDF report by email.
Two-way Tally Prime
Tally pulls printed challans through an authenticated API. SteelERP pushes to a webhook you provide.
WhatsApp challans
Challan PDFs sent from your own WhatsApp Business account.
Access and data
Role-based access with yard scoping, an audit log and an optional IP allow-list for non-admin users. Each customer gets a separate database, hosted on AWS Mumbai.
Optional extras: a customer portal so your buyers can see their own orders, an AI advisor that runs on your own Anthropic API key, and daily backups to S3. The interface is in English and Hindi.
What SteelERP does not do
We'd rather you hear this now than find out after go-live:
- It does not connect to weighbridge hardware. You enter the actual weight from the slip.
- It does not generate e-way bills or e-invoice IRNs.
- It does not do GPS tracking of trucks, and it has no automatic credit-lock.
Bill TMT on what was actually loaded
Walk through a TMT order in the live sandbox, from inquiry to order to part delivery to bill. The Starter plan is ₹10,000/month for up to 10 users and 1 stockyard. Growth and Enterprise are on a custom quote.
Try Live Sandbox Get a QuoteTMT bar software — FAQs
Can SteelERP bill TMT on actual weight when the order was taken in bars or tonnes?
Yes. Each order item carries the ordered weight and the actual loaded weight, and the bill is raised on the actual weight. Delivery sub-orders can be counted in kg, metres or pieces, and SteelERP converts the quantities to tonnage.
How do I set up TMT brands, grades and sizes in SteelERP?
The product catalogue holds products, their sizes and their HSN codes. You can set up each brand and grade combination as a product, for example one mill's Fe 500D, and list the bar diameters you stock as its sizes.
Why does the actual weight of TMT bars differ from the weight chart?
IS 1786:2008 gives a nominal mass per metre for each bar size and allows a tolerance on it. For a batch, the tolerance is plus or minus 7 percent for sizes up to 10 mm, plus or minus 5 percent over 10 mm up to 16 mm, and plus or minus 3 percent over 16 mm. So the same count of bars can weigh more or less than the chart figure.
Does SteelERP read the weight from my weighbridge?
No. SteelERP does not connect to weighbridge hardware. You enter the actual loaded weight from the weighbridge slip against the delivery, and the bill uses that figure.
Does SteelERP generate e-way bills or e-invoices?
No. SteelERP calculates CGST, SGST or IGST on each order line with the HSN code, reports TCS, and exchanges data with Tally Prime, but it does not generate e-way bills or e-invoice IRNs.
Can I manage TMT stock across more than one yard?
Yes. Stock is held per warehouse, each user can be restricted to their own yard, and low-stock reports and advisory reorder suggestions help you plan purchases size by size. The Starter plan covers 1 stockyard; for more yards, ask for a Growth or Enterprise quote.
How much does SteelERP cost for a TMT trading business?
The Starter plan is ₹10,000 per month for up to 10 users and 1 stockyard. Growth and Enterprise plans are priced on a custom quote.
Sources for the standards on this page
- IS 1786:2008, High strength deformed steel bars and wires for concrete reinforcement (Bureau of Indian Standards), with Amendment No. 1 (November 2012) text on nominal sizes and the Fe number: IS 1786:2008
- Amendment No. 3 (March 2017) to IS 1786:2008, clause 1.1 grades Fe 415 to Fe 700: IS 1786:2008
- BIS Product Manual for IS 1786:2008 (PM/IS 1786/4, July 2020), grade groups and marking: bis.gov.in product manual
- Tata Nexarc, steel bar weight chart, on 12 m bars, per-kg or per-tonne pricing and weighbridge billing: blog.tatanexarc.com/da/steel-bar-weight-chart