Every steel pipe quotation starts with one number: steel pipe weight. Mills sell by the tonne, transporters charge by the tonne, and buyers compare landed cost per metre. If your weight is even 3% off, your margin, freight estimate and container planning are off too. The good news is that pipe weight is easy to calculate once you know the formula.
This guide shows the formula, the constants for common metals, and worked examples you can use in your next quote.
The basic formula
A pipe is a hollow cylinder. Its weight per metre is the cross-section area of the metal multiplied by the density of the material.
For carbon steel (density 7.85 g/cm³), this simplifies to:
Weight (kg/m) = (OD − WT) × WT × 0.02466
where:
- OD = outside diameter in millimetres
- WT = wall thickness in millimetres
- 0.02466 = a constant that combines π and the density of carbon steel
Multiply the result by the total length in metres to get the total weight.
Why the formula works
The area of a pipe wall is π × (OD − WT) × WT. Multiplying by the density of steel (7.85 g/cm³) and converting units gives π × 7.85 / 1000 ≈ 0.02466. So the constant only changes when the material changes.
Constants for other metals
| Material | Approx. density (g/cm³) | Constant |
|---|---|---|
| Carbon / mild steel | 7.85 | 0.02466 |
| Stainless steel 304 / 316 | 7.93 – 8.00 | 0.0249 – 0.0251 |
| Aluminium | 2.70 | 0.00848 |
| Copper | 8.96 | 0.02815 |
| Brass | 8.50 – 8.73 | 0.0267 – 0.0274 |
Stainless steel is slightly heavier than carbon steel, so using the carbon steel constant for SS pipes underestimates the weight by around 1–2%. On a full container, that difference is significant.
Worked examples
Example 1: 2" SCH 40 carbon steel pipe
- OD = 60.3 mm, WT = 3.91 mm
- (60.3 − 3.91) × 3.91 × 0.02466 = 5.44 kg/m
- A standard 6 m length weighs about 32.6 kg
Example 2: 4" SCH 40 carbon steel pipe
- OD = 114.3 mm, WT = 6.02 mm
- (114.3 − 6.02) × 6.02 × 0.02466 = 16.07 kg/m
- 100 metres weighs about 1.61 tonnes
Example 3: 2" SCH 10S stainless steel 316L pipe
- OD = 60.3 mm, WT = 2.77 mm
- (60.3 − 2.77) × 2.77 × 0.0251 = 4.00 kg/m
Example 4: 50 NB Medium class MS pipe (IS 1239)
- OD ≈ 60.3 mm, WT = 3.6 mm
- (60.3 − 3.6) × 3.6 × 0.02466 = 5.03 kg/m (plain end, black)
Want these answers in seconds? Use our free pipe weight calculator — it supports steel, stainless, aluminium, copper and more.
Theoretical vs actual weight
The formula gives the theoretical weight. Actual weight can differ because of:
- Manufacturing tolerances. Standards allow wall thickness to vary, for example −12.5% under ASTM A106 and A53. Pipes made on the thin side weigh less.
- Galvanising. A zinc coating adds weight — typically a few percent depending on size and coating thickness.
- Ends and sockets. Threaded pipes with sockets weigh slightly more per length than plain end pipes.
- Coatings and linings. Epoxy, 3LPE or cement linings add considerable weight.
When you quote by weight, say clearly whether the price is on theoretical or actual weighbridge weight. This one line avoids many disputes after delivery.
Using weight in your quotations
- Quote per metre and per tonne. Overseas buyers often think in price per metre or per piece; your mill thinks in tonnes. Showing both builds trust.
- Plan containers by weight. A 20 ft container usually reaches its weight limit before it is full of pipe. Calculate total tonnage before promising quantities.
- Check freight early. Sea and road freight estimates depend on gross weight, so add packing and bundling materials to the net weight.
- Show your working. A quotation that lists OD, WT, kg/m and total weight looks professional and reduces back-and-forth.
QuoteMitra, our quotation software for metal traders, calculates weights automatically as you add items, so every quote carries correct weights and totals.
Frequently asked questions
Is the pipe weight formula accurate for galvanised pipes?
The formula gives the weight of the black steel only. Add the weight of the zinc coating, which depends on coating thickness and pipe size, for a galvanised pipe.
Why is my weighbridge weight different from the calculated weight?
Wall thickness tolerances, coatings, sockets and packing materials all change the actual weight. Agree in advance whether you sell on theoretical or actual weight.
Can I use the same formula for square and rectangular tubes?
No. Hollow sections need a different formula based on their perimeter and corner radius. Use a dedicated calculator or the manufacturer's weight table for those.
How do I convert kg per metre to pounds per foot?
Multiply kg/m by 0.672 to get pounds per foot. To get kg per foot, multiply kg/m by 0.3048.
Quick checklist
- Confirm OD and wall thickness from the standard, not from memory.
- Use the right constant for the material.
- State theoretical or actual weight.
- Include coating and packing in shipping weight.
- Double-check totals before sending the quote.
Accurate weights are a small detail that buyers notice. A supplier who gets them right every time looks like a supplier who gets the product right too.
