Stainless Steel Tube Sizes and Wall Thicknesses – Complete Table

Stainless Steel Tube Sizes and Wall Thicknesses – Complete Table

When ordering stainless steel tube, choosing the right size is often more difficult than choosing the material grade. The same outer appearance can hide very different wall thicknesses, the weight can vary significantly, and the tube may not meet the structural requirements of the project. This article brings together the most commonly used stainless steel tube sizes, standards, weights in kg/m, and practical selection guidance.

Tube size notation

A typical stainless steel tube size is written as Ø 42.4 × 2.0 mm. Ø 42.4 is the outside diameter, while 2.0 mm is the wall thickness. The inside diameter is calculated by subtracting twice the wall thickness from the outside diameter: 42.4 − 2 × 2.0 = 38.4 mm.

DN, NPS and real outside diameter

If a drawing specifies DN 50, the real outside diameter is 60.3 mm, not 50 mm. In the NPS system, 2″ corresponds to the same outside diameter. Decorative and structural tubes are usually specified directly by outside diameter in millimetres rather than by DN or NPS.

Common round tube sizes

Common stainless steel round tube sizes include Ø 6, 8, 10, 12, 16, 20, 25, 33.7, 38, 42.4, 48.3, 60.3, 76.1, 88.9, 114.3, 139.7, 168.3 and 219.1 mm. Typical wall thicknesses range from 1.0 mm for decorative applications to 6.0 mm or more for pressure and industrial use.

For handrails, Ø 42.4 × 2.0 mm is a widely used standard size. It is comfortable to grip and strong enough for typical bracket spacing. Smaller sizes such as Ø 33.7 mm are often used indoors, while Ø 48.3 mm is common in industrial settings.

Square and rectangular tubes

Square stainless steel tubes are common in frames, furniture, railings and support structures. Typical sizes include 20 × 20, 25 × 25, 30 × 30, 40 × 40, 50 × 50, 60 × 60, 80 × 80 and 100 × 100 mm. Rectangular tubes such as 40 × 20, 60 × 40, 80 × 40 and 100 × 50 mm are used when load is mainly applied in one direction.

Wall thickness selection

For decorative tubes that do not carry load, 1.0–1.5 mm is often sufficient. For indoor handrails, 1.5–2.0 mm is typical. Outdoor handrails should normally use at least 2.0 mm, and heavier structures should use 3.0 mm or more. Pressure tubes must be selected according to calculation and the relevant standard, usually EN 10217-7 for welded stainless pressure tubes.

Relevant standards

EN 10217-7 covers welded stainless steel pressure tubes. EN 10216-5 covers seamless stainless pressure tubes. EN 10296-2 covers welded stainless structural tubes, while EN 10297-2 covers seamless stainless structural tubes. EN 10204 3.1 defines the material certificate, which documents chemical composition and mechanical properties.

How to calculate tube weight

For a round tube, weight can be estimated with: weight = π × (OD − WT) × WT × density / 1,000,000. OD and WT are in millimetres, and density is approximately 7,900 kg/m³ for AISI 304 and 8,000 kg/m³ for AISI 316.

Before requesting a quote, confirm the outside diameter, wall thickness, material grade, finish, length, quantity, standard and certificate requirement. Kominox can supply common stainless steel tubes from stock and special sizes on request.