What is the formula for round tube weight?

Weight = (π ÷ 4) × (OD² − ID²) × Length × Density. OD is the outer diameter in meters, ID = OD − 2 × wall thickness, and density is in kg/m³. This gives the mass of the hollow steel wall.

What is the difference between a pipe and a round tube (CHS)?

Pipes are sized by nominal bore (NPS) and schedule; round tubes (CHS — Circular Hollow Sections) are sized by their actual outer diameter and wall thickness. This calculator uses actual dimensions, making it suitable for both.

What density is used for carbon steel?

Carbon steel / mild steel uses 7850 kg/m³, the standard value per EN 10210, EN 10219, and ASTM A500/A513 for structural hollow sections.

What is linear weight (kg/m)?

Linear weight is the mass per unit length of tube, typically expressed in kg/m. It is useful for ordering by length and is independent of the tube length you enter — it is the weight of a 1-metre section.

Can I enter dimensions in inches?

Yes. Each dimension field has its own unit selector. You can mix mm for the diameter and inches for the wall thickness if needed — the calculator converts all values to meters before computing.

How do I calculate weight for multiple tubes?

Enter the number of tubes in the Quantity field. The calculator multiplies the single-tube weight by the quantity to show the total batch weight alongside the per-tube weight.

Steel Round Tube Weight Calculator

Name: Steel Round Tube Weight Calculator
Availability: InStock
Author: Nham Vu

Enter outer diameter, wall thickness, and length to get the weight of a circular hollow steel tube (CHS) in kg/m, kg, and lbs instantly.

Tube Dimensions

Outer Diameter (OD)

Wall Thickness

Length

Material

Quantity (tubes)

Formula Reference

W = (π / 4) × (OD² − ID²) × L × ρ

OD = outer diameter (m), ID = OD − 2×t (m), t = wall thickness, L = length (m), ρ = density (kg/m³).

Enter tube dimensions on the left and click Calculate.

Common CHS Sizes — Carbon Steel (7850 kg/m³)

OD (mm)	Wall (mm)	ID (mm)	kg/m
21.3	2.0	17.3	0.95
33.7	2.6	28.5	1.99
42.4	3.2	36.0	3.09
60.3	3.2	53.9	4.51
76.1	4.0	68.1	7.11
101.6	4.0	93.6	9.63
114.3	5.0	104.3	13.50
168.3	6.3	155.7	25.20
219.1	8.0	203.1	41.60

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Summary

Enter outer diameter, wall thickness, and length to get the weight of a circular hollow steel tube (CHS) in kg/m, kg, and lbs instantly.

How it works

Enter the outer diameter (OD) of the round tube and select a unit (mm, cm, or in).
Enter the wall thickness of the tube in the same or a different unit.
Enter the tube length and choose the length unit (m, mm, ft, or in).
Select the tube material — the calculator uses its standard density automatically.
Optionally enter a quantity to calculate total weight for multiple tubes.
Click Calculate. Results show linear weight (kg/m), total weight in kg and lbs, inner diameter, and volume.

Use cases

Estimating CHS tube weight for structural steel fabrication.
Calculating freight and shipping weight for round tube orders.
Preparing bill of materials (BOM) for steel construction projects.
Comparing weights of different tube sizes or wall thicknesses.
Checking load capacity on tube frames, hangers, and supports.
Verifying theoretical tube weight against supplier mill certificates.
Mechanical design calculations for round hollow profiles.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu