TMT bar weight chart

This chart gives the theoretical weight of TMT bars from 6 mm to 40 mm - per metre, per 12 m bar and the approximate number of bars in a tonne. It uses the standard formula d x d / 162 (d in mm), which comes from the density of steel, 7,850 kg/m3.

Weight chart

Diameter	kg per metre	kg per 12 m bar	Bars per tonne (approx.)
6 mm	0.222	2.67	375
8 mm	0.395	4.74	211
10 mm	0.617	7.41	135
12 mm	0.889	10.67	94
16 mm	1.580	18.96	53
20 mm	2.469	29.63	34
25 mm	3.858	46.30	22
28 mm	4.840	58.07	17
32 mm	6.321	75.85	13
36 mm	8.000	96.00	10
40 mm	9.877	118.52	8

Theoretical weights. Actual weights vary within the rolling tolerance allowed by IS 1786.

Where the formula comes from

A bar of diameter d mm has a cross-section of pi x d x d / 4 mm2. One metre of it has a volume of that area x 1,000 mm, and steel weighs 7,850 kg per cubic metre. Working the units through gives d x d x 0.006165 kg/m - which is the same as d x d / 162.

Using the chart

Bar bending schedule to tonnes: add the cut lengths per diameter, multiply by kg/m, and add a wastage allowance.
Checking a delivery: weigh a few bars of each size and compare with the kg per 12 m bar column.
Comparing quotes: if one seller bills on theoretical weight and another on weighbridge weight, the totals will differ - agree the basis first.

Bundles

Mills bundle bars by size, and the number of bars per bundle varies between mills. Do not order "by bundle" unless the seller states the bars per bundle and the bundle weight in writing - order in tonnes instead.

Need the bars?

On Indian Steel Portal you float one inquiry for TMT bars - grade, sizes, quantity, preferred makes, delivery city and payment terms. KYC-verified mills, stockists and traders quote against it in a live reverse auction with a minimum decrement and a soft-close, ranked L1 to L4 on landed cost. You award L1 or any ranked bidder, and the deal note - with GST, MTC and weighment terms - is generated for both sides.

Float a TMT inquiry - free Steel weight calculator

Frequently asked questions

What is the weight of a 12 mm TMT bar?

0.889 kg per metre, so a 12 m bar weighs about 10.67 kg.

What is the weight of a 16 mm TMT bar per metre?

1.580 kg per metre; a 12 m bar weighs about 18.96 kg.

How many 8 mm TMT bars are in one tonne?

About 211 bars of 12 m length, by theoretical weight (4.74 kg per bar).

What is the formula for TMT bar weight?

d x d / 162 gives kg per metre, where d is the diameter in mm.

Why does actual TMT weight differ from the chart?

IS 1786 allows a rolling tolerance on mass per metre, so actual bars can be slightly lighter or heavier than the theoretical figure.

Last updated 8 October 2026.