How do I calculate the weight of steel pipe per foot?

Weight per foot = (OD − Wall Thickness) × Wall Thickness × 10.68. OD and wall thickness in inches; result in lbs/ft. Example: 6-inch Schedule 40 (OD=6.625, wall=0.280): (6.625 − 0.280) × 0.280 × 10.68 = 6.345 × 0.280 × 10.68 = 18.97 lbs/ft. Alternatively, look up the value in ASME B36.10 tables.

What does Schedule 40 mean for pipe?

Schedule number indicates wall thickness. Higher schedule = thicker wall = heavier pipe = higher pressure rating. Schedule 40 is the most common for general water and low-pressure service. Schedule 80 has thicker walls for higher pressure. The schedule system replaced the old Standard (STD), Extra Heavy (XH), and Double Extra Heavy (XXH) designations, though these terms are still used.

Why is nominal pipe size different from the actual pipe outside diameter?

NPS is a historical legacy designation from when pipe was sized by approximate inside diameter. When industry standardized on consistent ODs for all schedules (so the same fittings and threads work regardless of wall thickness), the inside diameter changed but the NPS number didn't. Above NPS 14, the OD happens to equal the NPS number in inches — but smaller sizes have no obvious relationship between NPS and OD.

How much does 100 feet of 6-inch Schedule 40 steel pipe weigh?

6-inch Schedule 40 weighs 18.97 lbs/ft. For 100 feet: 18.97 × 100 = 1,897 lbs (approximately 860 kg). Add water content if calculating water-filled weight: ID = 6.625 − 2×0.280 = 6.065 inches; volume = 6.065² × 0.0408 = 1.50 gallons/ft; water weight = 1.50 × 8.34 × 100 = 1,251 lbs. Total water-filled weight: 1,897 + 1,251 = 3,148 lbs.

How to Calculate Line Pipe Weight: Steel Pipe, Wall Thickness, and Schedule

Learn how to calculate steel line pipe weight per foot from nominal pipe size (NPS), wall thickness, and schedule numbers — with the standard formula and weight tables.

Related Calculators

Line Pipe Weight Calculator
Estimate steel line-pipe weight from outside diameter, wall thickness, length and material density.
Tank Volume Calculator
Calculate cylindrical tank volume in gallons from diameter and height measurements.

Steel Pipe Weight Formula

Weight per foot (lbs/ft) = (OD − Wall Thickness) × Wall Thickness × 10.68

This is derived from: W = π × (OD − t) × t × density_per_foot

Where: - OD = outside diameter in inches - t = wall thickness in inches - 10.68 = derived constant (steel density in lbs/in³ × π × 12 in/ft)

Total weight: W_total = Weight per foot × Total length (ft)

Worked Example: 4-inch Schedule 40 Pipe

NPS 4 (Nominal Pipe Size 4): - OD = 4.500 inches (NPS OD is standardized, NOT the nominal size) - Schedule 40 wall thickness = 0.237 inches

Weight per foot = (4.500 − 0.237) × 0.237 × 10.68 = 4.263 × 0.237 × 10.68 = 4.263 × 2.531 = 10.79 lbs/ft

This matches the API 5L published value of 10.79 lbs/ft for 4-inch Schedule 40.

NPS vs. OD: Why They Differ

Nominal Pipe Size (NPS) is a designator — the actual outside diameter differs, especially at small sizes:

NPS	Actual OD (inches)
1/2	0.840
3/4	1.050
1	1.315
1.5	1.900
2	2.375
3	3.500
4	4.500
6	6.625
8	8.625
10	10.750
12	12.750
16	16.000
20	20.000
24	24.000

Above NPS 14, OD equals the nominal size in inches.

Common Schedule Wall Thickness and Weight Table

NPS	Sch 40 Wall	Sch 40 lbs/ft	Sch 80 Wall	Sch 80 lbs/ft
1	0.133	1.68	0.179	2.17
2	0.154	3.65	0.218	5.02
3	0.216	7.58	0.300	10.25
4	0.237	10.79	0.337	14.98
6	0.280	18.97	0.432	28.57
8	0.322	28.55	0.500	43.39
10	0.365	40.48	0.593	64.40
12	0.406	53.52	0.687	88.51

API 5L and ASME B36.10 Standards

API 5L: Standard for line pipe used in oil & gas pipelines. Grades: A, B, X42, X52, X56, X60, X65, X70, X80 (numbers indicate minimum yield strength in ksi).

ASME B36.10: Standard for wrought steel pipe, all schedules. Used in process piping (ASME B31.3) and pressure piping.

Line pipe grades don't change the weight formula — weight depends only on geometry (OD and wall thickness), not steel grade.

Volume of Pipe (for fluid-filled weight)

Internal volume per foot (gallons/ft) = (ID² × 0.0408) Where ID = OD − 2 × wall thickness

Example: 4-inch Schedule 40 (ID = 4.500 − 2×0.237 = 4.026 inches) Volume = 4.026² × 0.0408 = 16.21 × 0.0408 = 0.661 gallons/ft

Water-filled 4-inch Schedule 40 line: 0.661 gal/ft × 8.34 lbs/gal = 5.51 lbs/ft extra Total water-filled weight: 10.79 + 5.51 = 16.30 lbs/ft

Related Guides

Frequently Asked Questions

How do I calculate the weight of steel pipe per foot?: Weight per foot = (OD − Wall Thickness) × Wall Thickness × 10.68. OD and wall thickness in inches; result in lbs/ft. Example: 6-inch Schedule 40 (OD=6.625, wall=0.280): (6.625 − 0.280) × 0.280 × 10.68 = 6.345 × 0.280 × 10.68 = 18.97 lbs/ft. Alternatively, look up the value in ASME B36.10 tables.
What does Schedule 40 mean for pipe?: Schedule number indicates wall thickness. Higher schedule = thicker wall = heavier pipe = higher pressure rating. Schedule 40 is the most common for general water and low-pressure service. Schedule 80 has thicker walls for higher pressure. The schedule system replaced the old Standard (STD), Extra Heavy (XH), and Double Extra Heavy (XXH) designations, though these terms are still used.
Why is nominal pipe size different from the actual pipe outside diameter?: NPS is a historical legacy designation from when pipe was sized by approximate inside diameter. When industry standardized on consistent ODs for all schedules (so the same fittings and threads work regardless of wall thickness), the inside diameter changed but the NPS number didn't. Above NPS 14, the OD happens to equal the NPS number in inches — but smaller sizes have no obvious relationship between NPS and OD.
How much does 100 feet of 6-inch Schedule 40 steel pipe weigh?: 6-inch Schedule 40 weighs 18.97 lbs/ft. For 100 feet: 18.97 × 100 = 1,897 lbs (approximately 860 kg). Add water content if calculating water-filled weight: ID = 6.625 − 2×0.280 = 6.065 inches; volume = 6.065² × 0.0408 = 1.50 gallons/ft; water weight = 1.50 × 8.34 × 100 = 1,251 lbs. Total water-filled weight: 1,897 + 1,251 = 3,148 lbs.

Last updated 7/28/2026