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⭕ ISO 1127 Stainless Steel Tube

Calculate weight and dimensions of stainless steel tubes according to ISO 1127.

Inputs

Results

Unit Weight (W)
0.00 lb/ft
Internal Flow Area
0.00
in²

Tube Cross-Section

OD = 60.3 mmt = 2.77 mm

Calculator Description

ISO 1127 is the international standard that specifies the dimensions, tolerances, and unit masses of stainless-steel tubes. This calculator applies that standard to determine a tube's theoretical mass per unit length and its internal flow area from the outer diameter and wall thickness.

What this calculator finds

From the outer diameter (D) and wall thickness (t), it calculates the weight per unit length (kg/m) and the internal cross-sectional flow area (A).

Why it matters

  • Estimating material weight for shipping, supports, and structural load design
  • Providing the flow area needed to compute flow rate, velocity, and pressure drop
  • Verifying exact specifications of standard tubes for quotations and procurement

Formula

ISO 1127 Tube Weight Formula

The unit mass is the cross-sectional area of the tube wall (an annulus) multiplied by the material density. The constant 0.0246615 packages π/4 together with the steel density (7.85 g/cm³) and the unit conversion.

W=(D−t) t×0.0246615W = (D - t)\,t \times 0.0246615
A=π4(D−2t)2A = \dfrac{\pi}{4}\left(D - 2t\right)^{2}
  • W — Weight per unit length [kg/m]
  • D — Outer diameter [mm]
  • t — Wall thickness [mm]
  • A — Internal flow area [mm²]
  • 0.0246615 — Density constant for steel (based on 7.85 g/cm³)

How the formula works

  • The (D − t)·t term is the wall annulus' mean diameter × thickness, proportional to the wall area — a thicker wall means more mass.
  • The inner diameter is D − 2t, so a thicker wall sharply reduces the internal flow area A.
  • For other metals (e.g. stainless 304 ≈ 7.9–8.0 g/cm³), scale the weight by the density ratio.

Worked example

For a tube with D = 33.7 mm and t = 2.0 mm, the weight is W = (33.7 − 2.0) × 2.0 × 0.0246615 ≈ 1.56 kg/m, and the internal area is A = (π/4) × (33.7 − 4.0)² ≈ 693 mm².

Useful Tips

Practical tips

  • The constant assumes carbon steel (7.85 g/cm³); stainless is about 1–2% heavier when corrected to its actual density.
  • Once you know the flow area A, you can find mean velocity directly from Q = A · v.

Limitations & cautions

  • These are theoretical values based on nominal dimensions; actual product may vary within the ISO 1127 tolerances.
  • Weld beads, surface treatments, and end machining are not included in the weight.