MS Pipe Weight Per Metre: IS 1239 Light, Medium and Heavy

MS pipe weight per metre ranges from 0.95 kg/m for 15mm NB Light class to 14.49 kg/m for 100mm NB Heavy class under IS 1239 Part 1, and is calculated using the formula: Weight = 0.02466 × t × (OD − t) — where t is wall thickness in mm and OD is outer diameter in mm.

What Is the MS Pipe Weight Formula?

The formula comes directly from the geometry of a hollow cylinder and the density of mild steel. The cross-sectional area of the pipe wall is π × t × (OD − t), and when you multiply by steel density (7.85 g/cm³) and convert units to kg/m, the constant π × 7.85 / 1000 simplifies to 0.02466.

So the working formula is:

Weight (kg/m) = 0.02466 × t × (OD − t)

Where:

• OD = outer diameter in millimetres
• t = wall thickness in millimetres

One critical point that catches people out: nominal bore (NB) is not the same as outer diameter. A 25mm NB pipe has an OD of 33.7mm — not 25mm. Always use the actual OD from the IS 1239 table, not the NB designation. Using NB in the formula instead of OD will give you a weight that is roughly 25–40% lower than the real figure, which can cause serious errors in procurement and transport planning.

Use our free Metal Weight Calculator → to get results for any pipe size instantly without manual arithmetic.

IS 1239 Part 1 — Light, Medium and Heavy Class Explained

IS 1239 Part 1: 2004 — Mild Steel Tubes, Tubulars and Other Wrought Steel Fittings — Part 1: Mild Steel Tubes — covers three wall thickness classes for each nominal bore. The outer diameter is identical across all three classes for a given NB. Only the wall thickness changes.

Here is how each class is typically applied on Indian job sites:

• Light class — thinnest wall; used for conduit, cable routing, low-pressure water lines, and temporary scaffolding. Lower cost per metre, but not suitable for threaded joints under pressure.
• Medium class — the standard workhorse. Used in plumbing, general fabrication, fire-fighting lines, and structural frames. Most APL Apollo and Tata Steel catalogue sizes default to Medium class.
• Heavy class — thickest wall; used in high-pressure pneumatic lines, heavy structural applications, and any system that requires screwed fittings to hold under load. Significantly heavier and more expensive per metre.

When a purchase order simply says "MS pipe 25mm" with no class specified, suppliers usually default to Medium class. Always confirm this in writing — a Light vs Heavy class error on a 100-pipe order changes your total material weight by over 900 kg.

Worked Example: 25mm NB Medium Class Pipe Order

On site, you'll often hear someone ask: "nali ka wajan per meter kitna hoga?" — how much does one metre of this pipe weigh? For a 25mm NB Medium class pipe, here is the full calculation step by step.

Given:

• Nominal bore: 25mm NB
• Class: Medium (IS 1239 Part 1: 2004)
• Outer diameter (OD): 33.7mm
• Wall thickness (t): 3.2mm
• Stock length: 6 metres (standard random length)
• Quantity required: 100 pipes

Step 1 — Weight per metre:
Weight = 0.02466 × t × (OD − t)
Weight = 0.02466 × 3.2 × (33.7 − 3.2)
Weight = 0.02466 × 3.2 × 30.5
Weight = 2.41 kg/m

Step 2 — Weight per 6m pipe:
2.41 × 6 = 14.46 kg per pipe

Step 3 — Total for 100 pipes:
14.46 × 100 = 1,446 kg (1.446 tonnes)

This fits comfortably within a single standard 5-tonne delivery truck. If you were ordering Heavy class instead of Medium for the same 100 pipes, the total would jump to 2,930 × 6 × 100 / 1000 = 1,758 kg — an extra 312 kg that affects both freight cost and structural load calculations.

Cross-check this result using the Metal Weight Calculator → — select Mild Steel, Hollow Section (Round), enter OD 33.7mm, WT 3.2mm, length 6000mm, quantity 100.

MS Pipe Weight Per Metre Chart — IS 1239 Part 1 (15mm to 100mm NB)

All weights below are calculated using the formula 0.02466 × t × (OD − t) with wall thicknesses specified in IS 1239 Part 1: 2004. Values are rounded to two decimal places.

Source: IS 1239 Part 1: 2004. Weights calculated using W = 0.02466 × t × (OD − t). NB = Nominal Bore; WT = Wall Thickness.

APL Apollo MS Pipe and IS 1239 — What the Brand Listings Mean

If you're sourcing from a distributor, you'll see APL Apollo, Tata Steel, or Jindal Pipes listed against sizes like "25mm MS pipe medium IS 1239." What this means is that the pipe's OD, wall thickness, and minimum tensile strength conform to IS 1239 Part 1: 2004. The weight per metre values in the table above apply directly to these branded pipes — no correction factor is needed.

APL Apollo is the largest MS ERW pipe manufacturer in India and their catalogues list weight per metre for each NB and class, typically matching the formula values within ±0.02 kg/m. For a 50mm NB medium class pipe, their catalogue lists 5.03 kg/m — exactly what the formula gives for OD 60.3mm and WT 3.6mm. This matters for two reasons: first, it confirms that the formula is reliable for procurement; second, it means you can use APL Apollo's published weight data to back-check your own calculations on any project BOM.

One thing to verify with any supplier: whether they are supplying IS 1239 Part 1 (MS tubes) or IS 1239 Part 2 (MS tubulars and fittings). The Part 2 fittings — tees, elbows, couplings — have different dimensional tolerances and are not used in the weight-per-metre calculation above.