What formula is used to calculate iron pipe weight?

The formula is: Weight = (π ÷ 4) × (OD² − ID²) × Length × Density. OD is the outer diameter, ID = OD − 2 × Wall Thickness. This gives the volume of the pipe wall (hollow cylinder), which is then multiplied by the material density to get weight.

What density should I use for cast iron?

The material menu provides typical estimating values, not certified values. Density varies with alloy and manufacturing. For purchasing, lifting, support, or compliance work, enter the density from the supplier datasheet or mill certificate and compare the result with the published pipe weight.

What is the difference between cast iron and ductile iron pipe?

Cast iron (gray iron) is brittle and used in legacy water and sewer systems. Ductile iron (nodular cast iron) is stronger and more flexible, making it the modern standard for pressure water mains and municipal piping. Their densities are similar but ductile iron is preferred for new installations.

How do I find the wall thickness of an iron pipe?

Use the actual measured wall thickness or the value in the applicable manufacturer datasheet or mill certificate. Do not infer wall thickness from nominal diameter alone: product standards, classes, tolerances, linings, and connection designs can differ.

Can I calculate weight for multiple pipes at once?

Yes. Enter the number of pipes in the Quantity field. The calculator multiplies the single-pipe weight by that quantity and displays the total, while also showing the per-pipe weight for reference.

Does the weight include water inside the pipe?

No. Add the contents separately: water weight per meter = π ÷ 4 × ID² × 1,000 kg/m³. A pipe with a 311.6 mm ID holds about 76.3 kg of water per meter, more than the 51.2 kg/m of its 7.2 mm ductile iron wall.

Why is a ductile iron catalog weight higher than this result?

Supplier catalogs usually quote weight per meter including the socket or bell, and often the cement mortar lining and coating. This tool calculates the straight barrel only, so use the manufacturer table for a specific DN and pressure class when you need lifting or shipping weights.

How much does black iron pipe weigh per foot?

Black iron pipe is carbon steel to ASME B36.10. Schedule 40 weighs 0.85 lb/ft at 1/2 in, 1.13 at 3/4 in, 1.68 at 1 in, 2.27 at 1-1/4 in, 2.72 at 1-1/2 in, 3.65 at 2 in, 7.58 at 3 in, 10.79 at 4 in and 18.97 lb/ft at 6 in. Schedule 80 is heavier because the wall is thicker: 2 in Sch 80 weighs 5.02 lb/ft. A 21 ft random length of 2 in Sch 40 weighs about 77 lb.

How heavy is pipe full of water?

Water weight per foot = 0.3403 × ID² lb (ID in inches), or π ÷ 4 × ID² × 1,000 kg/m in metric. 2 in Sch 40 (ID 2.067 in) holds 1.45 lb of water per foot, so it weighs 5.10 lb/ft full. Use the water-filled weight for pipe support and hanger loads.

How much does ductile iron pipe weigh per foot?

AWWA C150/C151 uses a ductile iron density of 0.255 lb/in³, so the barrel weighs 9.613 × (OD − t) × t lb/ft. At the minimum Pressure Class 350, 4 in weighs 10.9 lb/ft, 6 in 16.0, 8 in 21.1, 10 in 27.1 and 12 in 34.8 lb/ft. Push-on or mechanical joint bells add weight per length, so manufacturer averages per foot are slightly higher.

What is linear weight (kg/m)?

Linear weight is the weight of one meter of pipe, useful when ordering pipe by length. It equals the total weight divided by the pipe length. The result is shown in both kg/m and lb/ft in the detailed breakdown.

Iron Pipe Weight Calculator

Look up black iron pipe weight per foot for Sch 40 and Sch 80 or ductile iron by pressure class, or enter any OD, wall and length to get kg, lb and water-filled weight.

Black iron pipe is carbon steel sized to ASME B36.10: 1/2 in Sch 40 weighs 0.85 lb/ft, 1 in 1.68, 2 in 3.65, 4 in 10.79 and 6 in 18.97 lb/ft (plain end, empty).

Pipe Dimensions

Standard size (optional)

Fills OD and wall in inches and sets the material. Length defaults to 1 ft if empty.

Outer Diameter (OD)

Wall Thickness

Length

Material

Preset densities are typical estimates. For critical work, use the value from the supplier datasheet or mill certificate.

Quantity (pipes)

Formula Reference

W = (π / 4) × (OD² − ID²) × L × ρ

Where OD = outer diameter (m), ID = OD − 2×t (m), t = wall thickness, L = length (m), ρ = density (kg/m³).

Enter pipe dimensions on the left and click Calculate.

Theoretical straight-barrel estimate

The result models a uniform hollow cylinder. It excludes hubs, bells, sockets, joints, fittings, linings, coatings, manufacturing tolerances, and pipe contents. Published product weights can therefore differ.

Use actual measured dimensions where available.
Use supplier or mill data for ordering, lifting, support design, and compliance.
All calculations run locally in your browser; entered values are not submitted by this tool.

References: ASTM A74 scope and DIPRA installation guides.

Black Iron Pipe Weight per Foot (Sch 40 & Sch 80)

Black iron pipe is carbon steel to ASME B36.10M. Plain-end weight in lb/ft; "water-filled" adds 62.4 lb/ft³ of water in the bore. Multiply by 1.488 for kg/m.

NPS (in)	OD (in)	Sch 40 wall	Sch 40 lb/ft	Sch 40 + water	Sch 80 wall	Sch 80 lb/ft	Sch 80 + water
1/8	0.405	0.068	0.24	0.26	0.095	0.31	0.33
1/4	0.540	0.088	0.42	0.47	0.119	0.54	0.57
3/8	0.675	0.091	0.57	0.65	0.126	0.74	0.80
1/2	0.840	0.109	0.85	0.98	0.147	1.09	1.19
3/4	1.050	0.113	1.13	1.36	0.154	1.47	1.66
1	1.315	0.133	1.68	2.05	0.179	2.17	2.48
1-1/4	1.660	0.140	2.27	2.92	0.191	3.00	3.56
1-1/2	1.900	0.145	2.72	3.60	0.200	3.63	4.40
2	2.375	0.154	3.65	5.10	0.218	5.02	6.30
2-1/2	2.875	0.203	5.79	7.86	0.276	7.66	9.50
3	3.500	0.216	7.58	10.78	0.300	10.25	13.11
3-1/2	4.000	0.226	9.11	13.39	0.318	12.50	16.35
4	4.500	0.237	10.79	16.31	0.337	14.98	19.96
5	5.563	0.258	14.62	23.29	0.375	20.78	28.66
6	6.625	0.280	18.97	31.49	0.432	28.57	39.87
8	8.625	0.322	28.55	50.23	0.500	43.39	63.18
10	10.750	0.365	40.48	74.65	0.594	64.43	95.55
12	12.750	0.406	53.52	102.02	0.688	88.63	132.66

Ductile Iron Pipe Weight per Foot (AWWA C151, Pressure Class 350)

Barrel (plain-end) weight = 9.613 × (OD − t) × t lb/ft at 0.255 lb/in³ (AWWA C150). Bells, cement-mortar lining and coatings are extra. 14–24 in pipe is also made in lighter classes 250 and 300.

Size (in)	OD (in)	Wall (in)	Barrel lb/ft	+ water lb/ft	Barrel kg/m
3	3.96	0.25	8.9	13.0	13.3
4	4.80	0.25	10.9	17.2	16.3
6	6.90	0.25	16.0	29.9	23.8
8	9.05	0.25	21.1	46.0	31.5
10	11.10	0.26	27.1	65.2	40.3
12	13.20	0.28	34.8	89.2	51.8
14	15.30	0.31	44.7	118.0	66.5
16	17.40	0.34	55.8	150.9	83.0
18	19.50	0.36	66.2	186.3	98.6
20	21.60	0.38	77.5	225.3	115.4
24	25.80	0.43	104.9	316.6	156.1

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Quick answer

Black iron pipe is carbon steel sized to ASME B36.10: 1/2 in Sch 40 weighs 0.85 lb/ft, 1 in 1.68, 2 in 3.65, 4 in 10.79 and 6 in 18.97 lb/ft (plain end, empty). Water adds 0.3403 × ID² lb/ft (ID in inches). Ductile iron barrel weight = 9.613 × (OD − t) × t lb/ft (AWWA, 0.255 lb/in³); 6 in Pressure Class 350 is 16.0 lb/ft.

Examples

Pipe	Empty	Water-filled
1 in Sch 40 black iron	1.68 lb/ft	2.05 lb/ft
2 in Sch 40 black iron	3.65 lb/ft	5.10 lb/ft
4 in Sch 40 black iron	10.79 lb/ft	16.31 lb/ft
6 in ductile iron PC350	16.0 lb/ft	29.9 lb/ft
12 in ductile iron PC350	34.8 lb/ft	89.2 lb/ft

Pick a standard size or enter your OD, wall, length and quantity to get the total in kg and lb, empty and full of water.

Summary

Look up iron pipe weight per foot in two charts: black iron (carbon steel) pipe to ASME B36.10 in Schedule 40 and 80 from 1/8 to 12 in, and ductile iron pipe to AWWA C151 at Pressure Class 350. Both show empty and water-filled weight. For any other pipe, the calculator uses the hollow-cylinder formula (π/4) × (OD² − ID²) × length × density, with ID = OD − 2 × wall. It reports kg, lb, kg/m, lb/ft and the water-filled total. Results exclude hubs, bells, linings, coatings and fittings, so use supplier or mill data for purchasing, lifting and compliance decisions.

How it works

Pick a standard size (black iron Sch 40/80 or ductile iron PC350) to fill OD, wall and material, or enter your own.
Enter the outer diameter (OD) of the pipe and select a unit (mm, in, or cm).
Enter the wall thickness and select a unit.
Enter the pipe length and select a unit (m, mm, ft, or in).
Choose a typical material-density estimate, or enter the density stated by your supplier or mill certificate.
Optionally enter a quantity to calculate total weight for multiple pipes.
Click Calculate Weight — the tool applies W = (π/4) × (OD² − ID²) × L × ρ and shows results in kg and lbs.

Use cases

Estimating straight pipe-barrel weight during early planning.
Calculating shipping and freight weight for iron pipe orders.
Preparing a bill of materials (BOM) for construction or fabrication projects.
Comparing weights of cast iron vs. ductile iron vs. steel pipe options.
Screening approximate loads before a qualified support or lifting review.
Verifying theoretical weight against supplier data sheets or mill certificates.
Pipe rack and spool weight calculations for plant and process design.
Budgeting material cost by knowing pipe weight before ordering.

Frequently Asked Questions

Last updated: 2026-10-10 · Reviewed by Nham Vu