HSS Weight per Metre: Chart and How to Calculate It

The weight of an HSS (hollow structural section) depends on its outside size and wall thickness. An HSS 102x102x6.4 (4 x 4 x 1/4 in) weighs about 18.2 kg/m (12.2 lb/ft), and you can calculate any square or rectangular size with kg/m = 0.0157 x t x (B + H minus 3.3t), using millimetres. For round HSS the formula is kg/m = 0.02466 x t x (D minus t). The chart below lists common sizes, and the sections after it show the formulas at work.

HSS weight chart: square and rectangular

Mass values match the CISC structural section tables and the AISC Shapes Database nominal weights; lb/ft is converted and rounded. The 6 m column is only a reference for handling and delivery, not a stock length. For how the designations work and Class C vs Class H, see our HSS size chart.

HSS weight chart: round

Notice that tubes with the same perimeter and wall weigh the same: HSS 152x152x6.4 and HSS 203x102x6.4 are both 28.3 kg/m. The steel is just arranged differently.

The HSS weight formulas

Every steel weight calculation is volume times density. Structural steel is taken as 7,850 kg/m³, which works out to 0.00785 kg per mm² of cross-section per metre of length. For a tube, the cross-section is the outer shape minus the hollow inside.

Square and rectangular HSS

kg/m = 0.0157 x t x (B + H minus 3.3t)

• B and H are the outside dimensions in mm
• t is the wall thickness in mm

Without the "minus 3.3t" term, the formula would assume square corners. Real tubes have rounded corners, and the correction allows for them. Checked against the chart above, it reproduces the published values within about 1% across the sizes listed.

Example: HSS 102x102x6.4

The designation rounds the imperial dimensions, so use the exact values: B = H = 101.6 mm (4 in) and t = 6.35 mm (1/4 in).

• B + H = 203.2 mm
• 3.3 x 6.35 = 21.0 mm
• 203.2 minus 21.0 = 182.2 mm
• 0.0157 x 6.35 x 182.2 = 18.2 kg/m

That matches the table. Using the rounded 102 and 6.4 instead gives 18.4 kg/m, close enough for a rough check but not exact.

The exact wall thicknesses behind the metric names are 4.8 = 4.76 mm (3/16 in), 6.4 = 6.35 mm (1/4 in), 7.9 = 7.94 mm (5/16 in), 9.5 = 9.53 mm (3/8 in) and 13 = 12.7 mm (1/2 in).

Round HSS

kg/m = 0.02466 x t x (D minus t)

• D is the outside diameter in mm
• t is the wall thickness in mm

This is the area of a ring (pi x t x the mean diameter) times 0.00785.

Example: 168.3 mm x 6.4 mm wall

• D minus t = 168.3 minus 6.35 = 161.95 mm
• 0.02466 x 6.35 x 161.95 = 25.4 kg/m

Converting to imperial

• kg/m x 0.672 = lb/ft
• lb/ft x 1.488 = kg/m

So the 18.2 kg/m tube is 18.2 x 0.672 = 12.2 lb/ft, which matches the imperial nominal weight for an HSS 4x4x1/4.

Calculating the weight of HSS posts and frames

Real HSS members rarely go out as bare tube. Posts get base and cap plates, frames get clips and gussets. The process:

1. Work out the total tube length for each size and multiply by kg/m.
2. Work out each plate as length x width x thickness x 7,850 kg/m³ (or use our steel plate weight calculator guide).
3. Add them up.

Example: four basement posts (plate sizes for illustration only; yours come from the drawings)

Each finished post weighs about 76 kg, which tells you a basement install needs at least two people per post, and that stairs and tight corners need planning.

For a general method that covers beams, channels, angles and plate as well as tube, see how to calculate structural steel weight.

Things that change the weight

The chart and formulas give nominal weights. A few real-world factors move the number slightly:

• Wall thickness tolerance. Tube is produced to a tolerance on wall thickness, so actual mass can differ a little from nominal. A scale ticket rarely matches the calculation exactly.
• Material standard. Canadian HSS to CSA G40.20/G40.21 and US tube to ASTM A500 can be the same nominal size. The weight tables use nominal thickness either way, but US design tables use a reduced design wall for many A500 tubes when calculating strength properties. Our HSS size chart explains why that matters to the engineer.
• Galvanizing. Zinc coats the outside and, on vented tubes, the inside as well, adding weight. If weight is critical, ask the galvanizer.
• Pipe vs HSS. A steel pipe can share an outside diameter with a round HSS but follow a different standard and wall thickness series. Calculate pipe weight from its actual wall, not from an HSS table.

Why HSS weight matters

• Ordering and estimating. Steel is commonly estimated and bought by weight, with fabrication added on top.
• Handling. Knowing the piece weight tells you how many people or what equipment you need, especially for basement posts carried down stairs.
• Delivery. Total weight and the longest piece decide the truck.
• Dead load. The self-weight of posts and frames is part of the load the engineer designs for.

What weight does not tell you is capacity. Two tubes of the same weight can carry very different column loads depending on their shape and height. That is a design question; see our explainer on structural steel post sizes for the sizes typically used.

Getting HSS cut and fabricated

We supply HSS cut to length and fabricate HSS posts with base and cap plates welded on, plus HSS frames to shop drawings, with CWB certified shop welding and delivery across the GTA and Ontario. Send us a list of sizes and lengths, or your drawings, and we'll do the take-off.

Request a quote, or browse our steel products for posts, plates, beams and channels.