Steel Pipe Weight Calculation: Formula, Chart, and Worked Examples

Steel pipe weight per metre is W = (OD − t) × t × 0.0246615, with outside diameter and wall in millimetres and W in kg/m. In US units it is W = (OD − t) × t × 10.69 in lb/ft. For NPS 8 XS (219.07 mm × 12.70 mm) that gives 64.64 kg/m (43.43 lb/ft), the same figure ASME B36.10M-2018 Table 2.1 prints. Below are the formula, a chart for NPS 2 through NPS 24, worked shipment examples, and the purchase-order mistakes that come from confusing theoretical weight with shipping weight.

Container payload limits, crane lift capacities, freight cost per tonne and customs duty declarations all turn on this number, and it is routinely pulled from the wrong table. ZC Steel Pipe supplies seamless and welded carbon steel line pipe per ASME B36.10M-2018 in sizes from NPS 1½ through NPS 60. All weight data below is sourced from ASME B36.10M-2018 Table 2.1, and every NPS 6 figure uses the 168.27 mm (6.625 in) OD from that table.

The Steel Pipe Weight Formula

Plain-end weight for wrought carbon steel pipe has two equivalent expressions, one per unit system:

Metric (SI):

W = (OD − t) × t × 0.0246615

• W = weight in kg/m
• OD = outside diameter in mm
• t = wall thickness in mm
• 0.0246615 = π × 7850 ÷ 10⁶ (7850 kg/m³ is the density of carbon steel; the wall cross-section is exactly π × (OD − t) × t in mm², and multiplying by density and dividing by 10⁶ gives kg/m). API 5CT uses the same constant to calculate its plain-end masses (Annex G, Equation G.13).

Imperial (US customary):

W = (OD − t) × t × 10.69

• W = weight in lb/ft
• OD = outside diameter in inches
• t = wall thickness in inches
• 10.69 is the USC constant API 5L 46th edition gives in Section 9.11 (Dimensions, Mass, and Tolerances), where the same equation carries C = 0.02466 for SI units. It equals π × 0.2836 lb/in³ × 12 in/ft (0.2836 lb/in³ is the same carbon steel density in US units), 10.6915 before rounding, and it reproduces the lb/ft values in the chart below.

The formula calculates the cross-sectional area of the pipe wall (a thin annulus) and multiplies it by steel density. It is exact for plain-end pipe: no threads, no couplings, no end protectors. Tabulated values in ASME B36.10M Table 2.1 match it to two decimal places.

Worked Calculation — NPS 8 XS Seamless Pipe

NPS 8 XS (Extra Strong) is a standard process plant and high-pressure gas line size. ASME B36.10M dimensions:

• OD = 8.625 in (219.07 mm)
• Wall thickness = 0.500 in (12.70 mm)

Metric: W = (219.07 − 12.70) × 12.70 × 0.0246615 W = 206.37 × 12.70 × 0.0246615 W = 64.64 kg/m — matches ASME B36.10M-2018 Table 2.1

Imperial: W = (8.625 − 0.500) × 0.500 × 10.69 W = 8.125 × 0.500 × 10.69 W = 43.43 lb/ft — matches ASME B36.10M-2018 Table 2.1

Extending to a shipment:

API 5L Table 12 sets the length rules for random length plain-end pipe: for random length 12 (40 ft), each pipe is 4.27 m (14.0 ft) minimum and 13.72 m (45.0 ft) maximum, and the order item must average at least 10.67 m (35.0 ft). Within that band, the average is whatever you agreed with the mill, so the figures below assume a 12.0 m ordered average and are derived, not tabulated:

• Weight per joint = 64.64 × 12.0 = 775.7 kg
• For a 40-joint order: 40 × 775.7 = 31,028 kg = 31.0 MT

For container planning we work to 24–28 t of usable payload for a 20ft box and 26–28 t for a 40ft. Those are our own planning figures, not ISO or carrier numbers, and the real limit depends on the container, the carrier and the road weight rules at each end. On those figures 31 t does not fit in one container of either size, so plan for two. The arithmetic is simple, and it is still the step most often skipped at the inquiry stage.

Worked Calculation — NPS 6 Sch 160 Sour Gas Line Pipe

In 2023 we shipped 3,000 pieces of API 5L X70Q PSL2 sour-service line pipe to Africa for sour natural gas transmission: OD 168.28 mm (6⅝ in) × WT 18.26 mm, SCH 160, beveled ends, 11.2–12 m lengths, 3 mm 3LPE. The heavy SCH 160 wall was specified for internal pressures well above standard schedule ratings, which makes it a good test of the formula. The order records the OD as 168.28 mm; ASME B36.10M-2018 Table 2.1 gives 6.625 in as 168.27 mm, and since that is the basis of the chart below, the calculation uses 168.27 mm:

Metric: W = (168.27 − 18.26) × 18.26 × 0.0246615 W = 150.01 × 18.26 × 0.0246615 W = 67.55 kg/m — matches ASME B36.10M-2018 Table 2.1 (NPS 6, Sch 160)

Imperial: W = (6.625 − 0.719) × 0.719 × 10.69 W = 45.39 lb/ft — matches the same table row

Per 12-metre joint: 67.55 × 12.0 = 810.6 kg of bare steel. Across 3,000 pieces at the recorded 11.2–12 m lengths, that works out to roughly 2,270–2,430 tonnes of plain-end steel (derived: 3,000 × 11.2 m × 67.55 kg/m and 3,000 × 12 m × 67.55 kg/m), before the 3LPE coating and packaging are added. The coating weight is not in the formula at all, so get it from the coating applicator and carry it as a separate line.

Steel Pipe Weight Chart — NPS 2 to NPS 24

All values are plain-end weights from ASME B36.10M-2018 Table 2.1, carbon steel (7850 kg/m³). Common schedules shown for each size; for a full listing of all schedules and NPS sizes see the ASME B36.10M specification tables →

Two points to read carefully from this table: first, at NPS 12 and above, STD wall is fixed at 9.52 mm (0.375 in) regardless of pipe diameter — STD no longer scales up as NPS increases. Second, at NPS 12, Sch 40 and STD diverge: the Sch 40 row carries 10.31 mm wall while STD is 9.52 mm. Ordering "NPS 12 Sch 40" and "NPS 12 STD" produces different pipe. Specify wall thickness in mm on the purchase order to eliminate ambiguity.

Plain-End Weight vs. Thread-and-Coupling Weight

Plain-end weight covers the pipe body only — cut square or beveled at both ends. Threaded-and-coupled (T&C) delivery adds one coupling screwed onto one pipe end before shipping, and that coupling adds weight the formula does not include. For line pipe it is the exception, not the rule: API 5L Section 9.12.1 furnishes threaded ends only for PSL 1 Grade L175P or A25P, sends other PSL 1 grades with plain ends unless another end finish is specified in the purchase order, and requires plain ends on all PSL 2 pipe. ASME SA-106 Section 19.1 likewise furnishes pipe with plain ends (square cut or beveled, by size and wall) unless otherwise specified.

ASME B36.10M does not publish T&C weights, and no flat percentage converts plain-end weight into T&C weight. You will see "add 2–4% for couplings" quoted, but no standard gives it. API 5CT handles OCTG size by size instead: Section 7.5, Equation (8) adds a tabulated end-finish mass gain or loss (em) to plain-end mass times length, and because em is a fixed mass per length rather than a share of the body weight, no single percentage holds across sizes. For any other threaded-and-coupled pipe, get the T&C weight basis from the mill in writing. The full method, including why the nominal threaded-and-coupled column is not the acceptance basis, is worked through in our casing tonnage calculation from joints and metres.

For plain-end beveled pipe — which is what API 5L PSL 2 and LSAW large-diameter pipe ship as — no coupling is added. Use plain-end weight from the table directly.

When NOT to Use the ASME B36.10M Formula

The formula is correct for wrought carbon steel line pipe and structural pipe sized to ASME B36.10M. It does not apply in these cases:

• API 5CT order mass: the formula gives casing and tubing plain-end mass correctly, but not the end-finish gain or loss (em) of Section 7.5 described above.
• Austenitic stainless steel (ASME B36.19M): density is higher than carbon steel. On our 7930 kg/m³ planning figure, multiply the formula result by 1.0102, or use a constant of 0.0249128 (= 0.0246615 × 7930 ÷ 7850) in the kg/m formula, and confirm the mill's density basis.
• Non-ferrous pipe (copper, aluminum, titanium): Density differs substantially. The formula is steel-specific and will produce large errors for non-ferrous materials.
• API 5L pipe ordered to a non-standard wall thickness: API 5L permits intermediate walls not listed in ASME B36.10M; the API 5L Table 9 range of permissible OD and wall combinations shows which ones. The formula still applies — substitute the actual ordered wall — but the weight will not appear in any standard table. Verify by calculation and carry the calculated value through logistics documents.
• Pipe with integral connections or upset ends: Some tubing products have upset ends that add mass locally. Source the weight from the manufacturer's dimensional drawing, not from the formula.

Manufacturing Tolerances and Their Effect on Actual Weight

ASME B36.10M sets the standard sizes; the outside diameter tolerance comes from the product specification the pipe is made to. For seamless carbon steel pipe to ASME SA-106, Section 16.2.1 points to Table 3 (ASME BPVC Section II Part A, 2023, page 174):

Table: permissible variations in outside diameter for ASME SA-106 pipe, Table 3

Above NPS 1½ the under-tolerance never moves from 0.8 mm (1/32 in) while the over-tolerance grows with size, so SA-106 pipe can run large but hardly small. The ±1 % figure you sometimes see quoted is not a general rule: Section 16.2.2 applies it only to pipe over 10 in (250 mm) OD that is ordered as special outside diameter tolerance pipe, and Section 16.2.3 sets ±1 % on the inside diameter for pipe over 10 in (250 mm) ID ordered as inside diameter tolerance pipe.

API 5L line pipe works to a proportional rule instead. Section 9.11.3.1 sends the diameter to Table 10 (API 5L 46th edition, page 39), where "pipe end" means the 100 mm (4.0 in) at each extremity (note a):

Table: API 5L diameter tolerances, Table 10, for the pipe body and the pipe end, in mm (in)

For seamless pipe the end tolerances apply up to 25.0 mm (0.984 in) wall, with thicker pipe as agreed (note b), and the diameter is measured as circumference divided by π (note d). The practical point for weight is how little OD tolerance moves it: NPS 8 XS at SA-106's full +1.6 mm over-tolerance works out at (220.67 − 12.70) × 12.70 × 0.0246615 = 65.14 kg/m, only about 0.8 % above the 64.64 kg/m nominal (derived).

Wall thickness tolerances come from the applicable product specification rather than from ASME B36.10M itself. For API 5L, they are in Table 11 (API 5L 46th edition):

Two footnotes to Table 11 matter for weight: if the purchase order specifies a smaller minus wall tolerance, the plus tolerance increases to keep the same range (note a), and the plus tolerance does not apply to the weld area of welded pipe (note c). Wall is where the weight really moves: the same NPS 8 XS at the full seamless +0.150t (14.605 mm) would calculate to about 73.64 kg/m, roughly 14 % heavy (derived), which is more than the mass tolerance below allows. ASME SA-106 is written differently and should not be read across from the API 5L table: Section 16.3 says only that "the minimum wall thickness at any point shall not be more than 12.5 % under the specified wall thickness."

The weight limit that actually caps an invoice dispute is the mass tolerance, not the wall tolerance. API 5L Section 9.14.1 holds each pipe to its nominal mass (length × mass per unit length) within +10.0 % / −3.5 % for ordinary grades, and +10.0 % / −5.0 % for special light sizes and Grades L175, L175P, A25 and A25P. Section 9.14.3 adds an order-item rule: for any order item of 18 tonnes (20 tons) or more, the total mass may not fall more than 1.75 % below nominal (3.5 % for the L175 and A25 grades). ASME SA-106 Section 16.1 sets the same +10 % / −3.5 % per length. So a single pipe can legitimately scale up to 10 % above its theoretical figure, while an order item of ordinary grades of 18 tonnes or more cannot come in more than 1.75 % light in total. Scale weight and the theoretical weight on the invoice are both compliant numbers, and they will rarely be the same number.

Purchase Order Guidance

Specifying the weight basis

Every purchase order for carbon steel pipe should state how weight is to be calculated for invoicing. Two options are in common use:

Theoretical plain-end weight means the mill invoices on ASME B36.10M formula weight multiplied by ordered length. Actual physical weight is not measured. The buyer pays for pipe meeting dimensional tolerances, regardless of whether the mill ran slightly heavy or light. Specify: "Invoice basis: theoretical plain-end weight per ASME B36.10M-2018."

Actual scale weight requires each pipe to be weighed at the mill or at the third-party inspection station. The invoice reflects what was actually produced. This protects the buyer if a mill consistently runs heavy (which systematically inflates invoices on a theoretical basis). Specify: "Invoice basis: actual scale weight per joint, measured at mill with third-party inspector present."

Procurement trap — packing list weight vs. invoice weight

The most specific mistake in this area: the mill issues a commercial invoice on theoretical pipe weight, and separately ships a packing list that states gross weight including packaging. Take a 100-joint NPS 8 STD order at 12.0 m (derived: 100 × 12.0 m × 42.54 kg/m = 51.0 MT of pipe), assuming 4 % packaging, about 53.1 MT gross. The freight forwarder uses the 53.1 MT figure for the shipping manifest, so the bill of lading says 53.1 MT while the commercial invoice says 51.0 MT, and nothing on either document explains the 2.1 MT difference. A gap the paperwork does not explain is exactly what a customs officer queries.

The correct approach: invoice on theoretical pipe weight, and state on the packing list separately: "Theoretical pipe weight [X] MT + packaging [Y] MT = gross [Z] MT." Every document then agrees on the pipe weight and accounts for packaging explicitly.

Minimum PO weight-related line items

• Specified OD in mm and wall thickness in mm — do not rely on schedule designation alone
• Stated weight per unit length expected: "Theoretical weight [xx.xx kg/m] per ASME B36.10M-2018"
• Invoice weight basis: theoretical (ASME B36.10M) or actual scale
• Packing list format: pipe weight and packaging weight stated separately

Use the unit converter → to cross-check kg/m and lb/ft values before submitting a purchase order.

Calculating Total Shipment Weight

For a standard API 5L beveled-end order in random lengths:

1. Read plain-end weight (kg/m) from the table above
2. Multiply by the average joint length on your order. For API 5L random length 12 plain-end pipe, Table 12 requires at least a 10.67 m (35.0 ft) average per order item, with individual pipes between 4.27 m (14.0 ft) and 13.72 m (45.0 ft), so use 10.67 m for the most conservative joint-count planning and your agreed average for tonnage
3. Multiply by joint count for total steel weight
4. Add a packaging allowance (plastic end caps, wooden dunnage, steel pipe bundle bands, bundle frames) to estimate gross shipping weight. We plan on 3–5 %, which is our own planning figure, not a standard value; the packing list gives the real number

Example (derived, assuming a 12.0 m ordered average): 60 joints of NPS 12 XS seamless (97.45 kg/m):

• Weight per joint: 97.45 × 12.0 = 1,169.4 kg
• Total steel: 60 × 1,169.4 = 70,164 kg = 70.2 MT
• Add an assumed 4% packaging: 70.2 × 1.04 = 73.0 MT gross

On our 26–28 t planning payload for a 40ft container, this order needs three containers, with the third only partly loaded. Ask your forwarder how a part-loaded container is charged before you fix the order quantity, because rounding the joint count to fill the last box can change the freight per tonne.

For OCTG casing and tubing plain-end masses by size, see the API 5CT specification tables →.