What formula is used?

Weight = (π ÷ 4) × (OD² − ID²) × Length × Density, where ID = OD − 2 × wall thickness. All dimensions are converted to meters and multiplied by the iron density of 7850 kg/m³ to obtain kilograms.

What iron density does this calculator use?

A density of 7850 kg/m³ is used. This is the standard value for mild steel and grey cast iron, both widely used in round tube and pipe applications. Stainless steel (7900–8000 kg/m³) or ductile iron (7100 kg/m³) would differ slightly.

What is the difference between outer diameter and wall thickness?

Outer diameter (OD) is the total outside measurement of the tube. Wall thickness is how thick the tube wall is. Inner diameter (ID) equals OD minus twice the wall thickness. The calculator shows an error if the wall thickness is too large for the given OD.

Which units are supported?

Diameter and wall thickness accept mm, cm, or inches. Length accepts mm, cm, m, inches, or feet. All values are converted to meters before the calculation runs.

Why must OD be greater than 2 × wall thickness?

If the wall thickness is equal to or greater than OD ÷ 2, the inner diameter would be zero or negative, which is physically impossible for a hollow tube. The calculator validates this and shows a clear error message.

Iron Round Tube Weight Calculator

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

Enter outer diameter, wall thickness, and length to get the weight of an iron round tube in kg and lb instantly.

Tube Dimensions

Outer Diameter (OD)

Wall Thickness

Length

Formula Reference

W = (π / 4) × (OD² − ID²) × L × ρ

Where OD = outer diameter (m), ID = OD − 2 × wall (m), L = length (m), ρ = 7850 kg/m³ (iron density), W = weight (kg).

Enter tube dimensions on the left and click Calculate.

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Summary

Enter outer diameter, wall thickness, and length to get the weight of an iron round tube in kg and lb instantly.

How it works

Enter the outer diameter (OD) of the tube and select a unit (mm, cm, or in).
Enter the wall thickness and select a unit (mm, cm, or in).
Enter the tube length and select a unit (mm, cm, m, in, or ft).
Click Calculate — the inner diameter is derived automatically as ID = OD − 2 × wall.
Weight is displayed in kilograms and pounds using an iron density of 7850 kg/m³.

Use cases

Estimating material weight for iron tube framing and structural projects.
Calculating shipping and freight weight for round iron tube orders.
Preparing a bill of materials for fabrication shops or purchasing departments.
Comparing wall thicknesses to balance structural strength and overall weight.
Verifying load and handling requirements before installation on site.
Quick field estimation of tube weight without manual calculation.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu