Steel Pipe Weight Calculator
Mass per metre, per length and in total from OD and wall thickness.
Quick answer
With the default inputs: Outside diameter 48 · Wall thickness 3 · Length each 6 etc.Total mass 199.75 kg
Edit the inputs below to recalculate.Inputs
Result
Total mass
199.75kg
| Mass per metre | 3.329kg/m |
| Mass each | 19.97kg |
| Total length | 60.00m |
| Inside diameter | 42.00mm |
| Section area | 424.1mm² |
| In tonnes | 0.200t |
| Metres per tonne | 300.4m/t |
| External surface area | 9.05m² |
| Internal surface area | 7.92m² |
The 0.02466 × t × (D − t) formula assumes 7.85 g/cm³ and applies to round tube only — square and rectangular hollow sections need their own formulas. Cheap tube sells at 2.5-2.8 mm wall, so weights come out light; scaffold checks must use the measured wall thickness.
Reverse: known result, work out one input
Enter a target result; the other inputs stay fixed and this one is worked out.
Formula
| Mass per metre | W = 0.02466 × t × (D − t) in kg/m |
| Underlying form | W = π(D − t) × t × 7.85 ÷ 1000 |
| Mass each | per metre × length |
| Total mass | mass each × quantity |
| Inside diameter | d = D − 2t |
| Section area | A = π/4 × (D² − d²) |
Φ48 × 3.0 mm, 6 m each, 10 lengths: 3.329 kg/m, 19.97 kg each, 60.00 m total, 199.75 kg overall, about 300 m per tonne and 9.05 m² of external surface.
How to work it out
- Confirm whether diameter and wall thickness are nominal or measured. Theoretical weight uses nominal, invoicing uses weighbridge, and a 3-6% difference is normal.
- Unit weight: W = (D − t) × t × 0.02466, with D and t in mm giving kg/m. The constant already folds in π and a density of 7.85 g/cm³.
- Multiply by the length for one piece, then by the count for the total. Six metres is the standard stock length; 9 and 12 m must be ordered.
- Divide by 1000 for tonnes, or use the unit weight directly when pricing by metre.
- For galvanised tube add the zinc: hot-dip coating is 3-6% by weight at 300-500 g/m², proportionally more on thin walls.
Where it goes wrong
- Treating the tube as a solid bar — a 48 × 3 tube is 3.33 kg/m, not the 14.2 kg/m of a solid 48 mm bar; the (D − t) term is what removes the bore.
- Ignoring the minus wall tolerance — standards allow ±10% and deliveries often come in under, so 100 t theoretical can weigh 94-97 t and pricing on theory loses money.
- Quoting galvanised tube at black tube weight — the zinc is 3-6%, roughly 40-60 kg per tonne at DN100, which adds up on volume work.
- Ignoring cutting loss on stock lengths — cutting 2.5 m pieces from 6 m yields two with 1 m of scrap, 16% waste, so net-length ordering falls short.
Material and cost
Welded steel tube (Q235) 4500-5500 CNY/t, hot-dip galvanised 5500-6800, seamless 6000-9000, stainless 304 18000-26000.
On site
- Scaffold tube at Φ48 × 3.0 is 3.33 kg/m, about 300 m per tonne; the older Φ48 × 3.5 was 3.84 kg/m, so state which when quoting.
- Stainless uses 0.02491 rather than 0.02466 because grade 304 is 7.93 g/cm³, not 7.85.
- Thin walls (t/D below 3%) vary more in weight, so structural work should be checked against measured thickness.
Basis
- GB/T 3091-2015 Welded steel pipes for low pressure liquid delivery
- GB/T 17395-2008 Dimensions, shapes, masses and tolerances of seamless steel tubes
- GB/T 6728-2017 Cold formed hollow steel sections for structural use
FAQ
Why must scaffold tube wall thickness be checked?
Because capacity falls almost linearly with wall thickness while price follows weight. Φ48 × 3.0 is 3.33 kg/m against 2.80 kg/m for 2.5 mm — 16% lighter but 18% less second moment of area, and more than that in buckling capacity. Using thin tube for high formwork support quietly drops the safety factor from 2 to 1.6, which is the recurring line in collapse reports.
How is square or rectangular hollow section weight calculated?
For a square use 0.00785 × t × (4a − 4t); for a rectangle replace 4a with 2(a + b). The general form is mid-line perimeter times thickness: W = 2(a + b − 2t) × t × 0.00785. Applying the round-tube formula overstates by 5-25%, worst as the section becomes square.
Does galvanising add to the weight?
Yes, though only slightly. A hot-dip coating of 60-85 µm weighs about 500-600 g/m² over both faces, which on Φ48 tube is 0.08-0.09 kg/m — roughly 2.5%. It is normally inside the quoted price, but on bulk orders check whether the supplier quotes black or galvanised weight.
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Steel Pipe Weight Calculator. 2026-10-25. https://jianzhujisuan.com/en/steel-pipe-weight
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.