TMT Bar Weight per Metre: 8 mm to 32 mm Chart & Formula

A TMT bar’s weight per metre is roughly its diameter squared divided by 162. A 12 mm bar weighs 0.888 kg/m, so one 12 m bar weighs about 10.7 kg. The full chart for 8 mm to 32 mm is below, with bars per tonne for planning truck loads.

Key takeaways

• Nominal mass per metre follows IS 1786 and is very close to d² ÷ 162.
• Weight depends only on diameter and length, not on grade (Fe 500D vs Fe 550D) or brand.
• Bills are usually raised on weighbridge weight, so expect small differences from the chart.
• Use bars-per-tonne to check delivery counts and plan site handling.

What is the weight of TMT bars per metre and per 12 m?

The table uses the nominal mass in IS 1786 and a 12 m bar, the most common mill length.

Diameter	Weight (kg/m)	Weight of one 12 m bar (kg)	Approx. bars per tonne
8 mm	0.395	4.74	211
10 mm	0.617	7.40	135
12 mm	0.888	10.66	94
16 mm	1.58	18.96	53
20 mm	2.47	29.64	34
25 mm	3.85	46.20	22
28 mm	4.83	57.96	17
32 mm	6.31	75.72	13

Bars per tonne = 1,000 ÷ weight of one 12 m bar, rounded. Actual counts at site can vary by one or two bars per tonne because of rolling tolerance.

You can also check these values on the TMT bars product page or calculate any length with our steel weight calculator.

How is the d²/162 formula derived?

The formula comes straight from geometry and the density of steel.

1. Cross-section area of a round bar = π × d² ÷ 4 (d in mm gives mm²).
2. One metre of bar has a volume of area × 1,000 mm.
3. Steel density is 7,850 kg/m³, which is 0.00000785 kg per mm³.
4. Weight per metre = π × d² ÷ 4 × 1,000 × 0.00000785 ≈ d² × 0.006165.
5. 1 ÷ 0.006165 ≈ 162, so weight ≈ d² ÷ 162 kg/m.

Example for 20 mm: 20 × 20 = 400, and 400 ÷ 162 = 2.47 kg/m.

How do you calculate the total weight for a project?

Multiply the weight per metre by the total running length for each diameter, then add them up.

1. Take the bar bending schedule (BBS) and total the running metres for each diameter.
2. Multiply each total by the kg/m value from the table.
3. Add 2–3% for laps and wastage if the BBS does not already include them.
4. Divide by 1,000 to get metric tonnes for your order.

Example: 1,800 m of 12 mm and 900 m of 16 mm. 12 mm: 1,800 × 0.888 = 1,598 kg. 16 mm: 900 × 1.58 = 1,422 kg. Total ≈ 3,020 kg, or about 3.02 MT before wastage.

Why does the delivered weight differ from the chart?

IS 1786 allows a tolerance on nominal mass, so rolled bars can be slightly lighter or heavier. That is why buyers compare the weighbridge slip with the invoice, not the chart value.

Two practical checks help:

• Weigh a few sample bars of each diameter on arrival and compare with the table.
• Ask for the mill test certificate (MTC) and check the heat number on the bundle tag against it. Our guide to the quality checks we follow explains what to look for.

Does brand or grade change the weight?

No. A 16 mm Fe 500D bar and a 16 mm Fe 550D bar have the same nominal mass. Grade affects yield strength, elongation and bendability, which matters for design, not for the weight calculation.

Brand affects price, availability and documentation, but not the kg/m figure. If you are comparing grades, see our TMT bars page for what each grade is typically used for.

How should I use weight when comparing prices?

Steel is quoted per tonne (or per kg), so always convert your requirement into tonnes before comparing quotes. Check whether a quote is ex-yard or delivered, and whether GST and freight are included.

For current indicative ex-Raipur rates, see TMT bar price today. Rates change often, so confirm the day’s rate before placing an order.

How RLG Ispat can help

RLG Ispat supplies TMT bars from 8 mm to 32 mm in Fe 500D and Fe 550D from Raipur, including SAIL, TATA and JINDAL brands on request, with GST billing and test certificates where applicable.

Send your diameter-wise quantities through the quote form or WhatsApp +91 75870 51838, and our sales desk will confirm availability, rate and dispatch.