This tool computes weight per length and total weight for a steel pipe. You can pick a pipe by NPS + Schedule from ASME tables or enter a custom OD + wall. Optional layers—corrosion allowance, outer coating, inner lining—and an optional fluid fill are supported. Results appear in kg/m and lb/ft, plus total kg and lb.
How to use it
- Choose Size mode:
- NPS + Schedule → select Standard, NPS, and Schedule. OD and wall auto-fill.
- Custom OD + Wall → type your OD and wall and pick their units.
- Enter Pipe length and its unit.
- Pick Material or set a Custom density.
- (Optional) Toggle Corrosion allowance, Outer coating, Inner lining, and Fluid inside, then fill their fields.
- Choose Decimal places for rounding.
- Press Calculate. Read Weight per length, Total weight, and Dimensions used.
Abbreviations Guide
- NPS: Nominal Pipe Size. A size label, not a direct measurement. For NPS ≤ 12 the label ≠ OD; for NPS ≥ 14 the label = OD (inches).
- SCH: Schedule. Wall-thickness series for a given NPS (5, 10, 20, 30, 40, 60, 80, 100, 120, 140, 160; stainless: 5S, 10S, 40S, 80S).
- STD: “Standard weight.” Industry alias for Schedule 40.
- XS: “Extra strong.” Industry alias for Schedule 80.
- XXS: “Double extra strong.” Heavier than XS.
- OD: Outside Diameter. The actual outside diameter of the pipe.
- ID: Inside Diameter. Computed bore: ID = OD − 2 × (t + CA + tlin). Clamped at ≥ 0.
- t: Wall thickness (nominal), from the schedule table or user input.
- CA: Corrosion allowance. Extra thickness added to the wall for service life and for weight.
- tcoat: Outer coating thickness.
- tlin: Inner lining thickness.
- ρ: Density of the pipe metal (kg/m³ or lb/ft³).
- ρcoat: Density of the outer coating.
- ρlin: Density of the inner lining.
- ρfluid: Density of the internal fluid.
- L: Pipe length used for total weight.
- kg/m: Kilograms per metre. Weight per unit length (SI).
- lb/ft: Pounds per foot. Weight per unit length (US).
- kg: Kilograms. Total mass.
- lb: Pounds. Total mass (US).
- kg/m³: Kilograms per cubic metre. Density unit (SI).
- lb/ft³: Pounds per cubic foot. Density unit (US).
- mm: Millimetre.
- cm: Centimetre.
- m: Metre.
- in: Inch.
- ft: Foot.
- DP: Decimal places. Number of digits shown after the decimal point.
Every setting explained
Size mode
NPS + Schedule: You select the pipe by its catalog label.
- Standard:
- ASME B36.10M — carbon/alloy steel pipes.
- ASME B36.19M — stainless steel pipes.
- NPS (Nominal Pipe Size): A size label. It is not a direct measurement. For NPS ≤ 12 the label is not equal to the OD; for NPS ≥ 14 the label equals OD in inches.
- Schedule (SCH): A wall-thickness series for a given NPS. Common sets: 5, 10, 20, 30, 40 (STD), 60, 80 (XS), 100, 120, 140, 160, and stainless variants 5S, 10S, 40S, 80S. Changing schedule changes wall thickness; OD stays fixed for that NPS.
- Outside diameter (in) and Wall thickness (in): Auto-filled from the standard you chose.
Custom OD + Wall: You enter the OD and Wall thickness yourself and pick their units (mm, cm, m, in, ft).
Pipe length
The length of pipe you want to weigh. Units: mm, cm, m, in, ft.
Material
- Carbon steel sets density to 7850 kg/m³.
- Stainless steel sets density to 8000 kg/m³.
- Custom density: Enter your own density and choose kg/m³ or lb/ft³.
Density affects only the metal mass. Coatings, linings, and fluid use their own densities.
Corrosion allowance (optional)
Extra thickness added to the nominal wall for weight calculations. Effective wall = wall + CA. Inside diameter reduces by 2 × CA. If CA is large enough to make the inside negative, the tool clamps the inside to zero.
Outer coating (optional)
A uniform layer on the outside. You provide:
- Coating thickness
- Coating density (e.g., zinc ~7130 kg/m³, paint/epoxy varies)
The tool adds the volume of a thin cylindrical shell around the pipe and multiplies by the coating density.
Inner lining (optional)
A uniform layer on the inside. You provide:
- Lining thickness
- Lining density (e.g., cement mortar ~1200 kg/m³ as a typical placeholder)
The tool subtracts lining from the flow diameter and adds the lining mass.
Fluid inside (optional)
Weight of the fluid occupying the inner bore (after lining). You provide:
- Fluid density (water ~1000 kg/m³ at 4 °C)
- Fluid-filled length (how much of the pipe is filled)
Decimal places
Controls display rounding for all numbers. Internal calculations use double precision.
Outputs explained
- Weight per length: Mass per meter and per foot (kg/m and lb/ft).
- Total weight: Mass of the specified length (kg and lb).
- Dimensions used: Echo of the actual geometry after options: OD, ID, wall, and length. ID reflects CA and lining.
Formulas and calculation details
Symbols below use meters and kilograms. Conversions handle all supported units.
- Inside diameter:
ID = OD − 2 × (wall + CA), clamped at 0. - Metal area per unit length (hollow cylinder):
Aₘ = (π/4) × (OD² − ID²). - Metal mass per unit length:
mₘ/L = ρ_metal × Aₘ. - Outer coating area per unit length:
A_c = (π/4) × ((OD + 2 t_c)² − OD²), mass per unit lengthm_c/L = ρ_coat × A_c. - Inner lining area per unit length:
A_ℓ = (π/4) × (ID² − (ID − 2 t_ℓ)²), mass per unit lengthm_ℓ/L = ρ_lin × A_ℓ. - Fluid area per unit length (after lining):
A_f = (π/4) × (ID − 2 t_ℓ)², mass per unit lengthm_f/L = ρ_fluid × A_f. - Total mass per unit length:
m/L = (mₘ + m_c + m_ℓ + m_f)/L. - Total mass for length
L:m_total = (m/L) × L. If the pipe is filled for a different lengthL_f, fluid mass usesL_f.
These are standard hollow-cylinder relations from elementary geometry. In imperial practice a common shortcut for bare steel is Weight/ft ≈ 10.69 × (OD − t) × t when OD and t are in inches and steel density ≈ 0.2836 lb/in³. The shortcut is consistent with the formulas above.
Units and conversions
- Lengths: mm, cm, m, in, ft → converted to meters for math.
- Densities: kg/m³ or lb/ft³ → converted to kg/m³ for math.
- Results: shown as kg/m and lb/ft, and as total kg and lb.
Data, standards, and scope
- Dimensions come from ASME pipe standards:
- B36.10M — wrought steel pipe (carbon/alloy).
- B36.19M — stainless steel pipe.
OD is fixed per NPS; wall depends on schedule. The widget includes a compact subset of those tables for fast lookup.
- Default densities: carbon steel 7850 kg/m³, stainless 8000 kg/m³, water 1000 kg/m³. Override if your specification requires different values.
Checks, limits, and good practice
- All thicknesses must be ≥ 0. The tool prevents negative ID.
- Use the same unit family for OD, wall, CA, coatings, linings, and length as you intend in practice.
- Real pipes have tolerances; standards prescribe thickness and diameter tolerances not modeled here.
- Temperature changes density; set custom densities if your case demands it.
Examples
- NPS 4, Sch 40 (B36.10M): OD = 4.500 in, wall = 0.237 in. With ρ = 7850 kg/m³ and no options:
- Weight per length ≈ 10.8 lb/ft (≈ 16.1 kg/m).
- Total weight for 6 m ≈ 96.6 kg.
- Custom: OD = 114.3 mm, wall = 6 mm, L = 6 m, ρ = 7850 kg/m³:
- Compute ID = 114.3 − 2×6 = 102.3 mm.
- Apply the hollow-cylinder formulas to get kg/m, then multiply by length.
Sources Used For Building The Calculator
- ASME B36.10M — Welded & Seamless Wrought Steel Pipe
- ASME B36.19M — Stainless Steel Pipe
- Nominal Pipe Size (NPS) — overview
- ASME/ANSI B36.10/19 — Pipe dimensions (metric)
- ASME/ANSI B36.10/19 — Pipe dimensions (imperial)
- ASME B36.10M — dimension tables (reference)
- ASME B36.19M — dimension tables (reference)
- Pipe weight formula 10.69·(OD−t)·t — NASPD
- Pipe weight per foot calculator — formula reference
- Annulus area A = π(R² − r²) — Wolfram MathWorld
- Cylindrical shells method — OpenStax Calculus
- Density of metals — Engineering ToolBox
- Water density equation — NIST GLP 10
What is your scenario of using this tool? Would you like to have any more features in it? Let us know in the comments below!
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