Pipe Weight Calculator

Background.

A pipe weight calculator turns a pipe specification into pounds. It matters far more often than it looks like it should: a truck has a payload limit, a rack has a shelf rating, a crew has to carry lengths up a ladder, a hanger has a working load, and an inspector wants to know what a suspended run weighs when it is full of water rather than when it is sitting empty on the ground. Those are four different numbers from the same pipe, and this page returns all of them.

The arithmetic is geometry plus a density. Inside diameter is the outside diameter minus twice the wall thickness. The metal seen end-on is a ring, and its area is π times the wall thickness times the outside diameter minus the wall thickness. Multiply that area by twelve inches to get the volume of one linear foot, multiply by the material density, and you have pounds per foot. Multiply by the run length and by the number of pieces and you have the total. Nothing more exotic than that is involved, which is why the answer is only as good as the two numbers going in: the published dimensions and the assumed density.

Substituting carbon steel's density of 0.2836 pounds per cubic inch into that chain collapses it to a single constant. Twelve times π times 0.2836 is 10.69, so weight per foot equals 10.69 times the outside diameter minus the wall, times the wall. That is the formula every mill, stockist and estimator quotes, and it is a special case of what this page computes rather than a different method. Because the general form is used here, changing the material to copper, stainless, PVC or CPVC changes only the density, and the calculator reports the density it used so the assumption is visible rather than buried.

The worked example is one twenty-foot length of two-inch Schedule 40 carbon steel. Two-inch iron pipe size has an outside diameter of 2.375 inches, and Schedule 40 puts a 0.154 inch wall on it. The metal ring is 1.0745315017 square inches, so the pipe weighs 3.6563919154 pounds per foot, or 5.4413106121 kilograms per metre. The twenty-foot length weighs 73.1278383086 pounds — 33.1702294914 kilograms — empty. Full of water it weighs 102.2039378562 pounds, because the bore holds about 29.08 pounds of water. That forty percent increase is the whole reason the filled figure is reported separately.

Two limits are stated openly. First, schedule and tube-type walls are minimum or nominal walls, so real pipe is made a little heavier than the specification and a mill certificate can read a few percent above these figures. Plastic pipe is the clearest case: this page computes 0.657 pounds per foot for two-inch Schedule 40 PVC while catalogues typically print about 0.68. Treat the result as a design and estimating weight, not as a shipping weight. Second, published weight tables themselves disagree slightly, because they were built from marginally different steel densities — ASME's tabulated six-inch Schedule 40 weight of 18.97 pounds per foot back-solves to 0.2833 pounds per cubic inch, while the 10.69 constant implies 0.2836. That spread is about a tenth of a percent, and this calculator lands inside it.

Weight also feeds decisions that are code-governed. Hanger and support spacing for water and drainage piping is prescribed by the plumbing code your jurisdiction has adopted, and adopted editions and local amendments vary between jurisdictions. Any structural load path carrying a long filled run falls under the adopted building code. Use these pounds as the input to that work and have a licensed plumber or engineer sign off before anything is hung.

What is pipe weight calculator?

Pipe weight is the mass of the pipe wall itself per unit length, normally quoted in pounds per foot or kilograms per metre. It is a function of exactly three things: outside diameter, wall thickness and material density. Nominal trade size does not appear in the formula at all — it only selects which outside diameter and wall thickness to look up.

The important distinction on this page is between empty weight and filled weight. Empty weight is what a mill invoices and what a truck carries. Filled weight is empty weight plus the water inside, and it is what a pipe hanger, a strut, a joist or a bracket actually has to hold once the system is commissioned. For small copper tube the difference is modest; for large steel or plastic pipe the water can weigh as much as the pipe or more.

Schedule numbers and copper tube types both work by changing wall thickness at a fixed outside diameter. Schedule 80 is heavier than Schedule 40 at the same nominal size; copper Type K is heavier than Type L, which is heavier than Type M. That is why the calculator asks for the schedule or type rather than just the size.

This calculator covers straight pipe. It does not include flanges, fittings, valves, insulation, cladding, coatings or lining, all of which add weight, and it does not compute stresses, spans or support spacing.

How to use this calculator.

1. 01Pick the schedule or copper tube type. This sets the published outside diameter and wall thickness.
2. 02Pick the nominal trade size. The 3, 4 and 6 inch options apply to Schedule 40 and 80 only; copper is tabulated here to 2 inch.
3. 03Pick the material. Density is what converts geometry into pounds, and Schedule 40 dimensions are shared by steel, PVC and CPVC, so pairing them is legitimate.
4. 04For anything not listed — a lined pipe, an alloy, a metric tube — set the schedule to Custom and enter the outside diameter and wall thickness, and set the material to Custom and enter the density in pounds per cubic foot.
5. 05Enter the length of one piece and how many pieces you have, then choose feet, inches or metres.
6. 06Read the empty weight as the headline number, and check the water-filled weight beside it before sizing any hanger or support.

The formula.

Start with the ring of material. Inside diameter is outside diameter minus twice the wall: for two-inch Schedule 40, 2.375 − 2 × 0.154 = 2.067 inches. The end-on area of the wall is π/4 times the difference of the squares of the two diameters, which simplifies exactly to π × t × (OD − t) — for this pipe, π × 0.154 × 2.221 = 1.0745315017 square inches. One linear foot of pipe therefore contains 1.0745315017 × 12 = 12.894378 cubic inches of steel. Carbon steel at 490 pounds per cubic foot is 490 ÷ 1728 = 0.283565 pounds per cubic inch, so a foot weighs 3.6563919154 pounds. Twenty feet weigh 73.1278383086 pounds. Metric conversion uses exact factors: 3.6563919154 lb/ft × 0.45359237 kg/lb ÷ 0.3048 m/ft = 5.4413106121 kg/m, and 73.1278383086 lb × 0.45359237 = 33.1702294914 kg. The contained water is computed from the bore rather than the wall: π × (2.067/2)² = 3.355603 square inches of cross-section, which over twenty feet is 3.4863428713 US gallons, and at 8.34 pounds per gallon that is 29.0760995476 pounds, giving a water-filled total of 102.2039378562 pounds. All arithmetic is carried at full precision and rounded only at the end, so weight per foot times length reproduces the total rather than drifting from it.

A worked example.

Frequently asked questions.

References& sources.

1. [1]ASME B36.10M, Welded and Seamless Wrought Steel Pipe — outside diameters, Schedule 40 and 80 wall thicknesses and tabulated plain-end weights. Standard is sold by ASME; the dimensional and weight rows used here were read from a republisher naming ANSI/ASME B36.10M-1995.
2. [2]Engineers Edge — Schedule 40 steel pipe sizes, dimensions and weight per foot, citing ANSI/ASME B36.10M-1995. Used as the independent target for the weight cross-check.
3. [3]Engineers Edge — copper tubing size chart to ASTM B88 (Types K, L and M outside diameter, wall thickness and inside diameter).
4. [4]Federal Steel Supply — steel pipe sizes and weights, giving the industry weight formula (OD − wall) × wall × 10.69 and the carbon steel density of 0.2836 lb/in³ (7.85 g/cm³) it is derived from.
5. [5]Spears Manufacturing — Physical Properties of PVC and CPVC Pipe: specific gravity 1.41 for PVC cell class 12454 and 1.55 for CPVC cell class 23447, measured to ASTM D792 under ASTM D1784 cell classification.
6. [6]California State Water Resources Control Board, Division of Drinking Water — operator certification examination conversion sheet (2016), giving the weight of water as 8.34 pounds per US gallon.