ForHosting KIT · Engineering & construction

Pipe weight calculator

A steel pipe with a 100 mm outer diameter, a 5 mm wall and 6 m of length weighs about 70.3 kg. Enter the four measurements and get the mass of the wall itself before you book the truck or the hoist. Free in your browser.

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Worked example

If you enter

Outer diameter: 100
Wall thickness: 5
Length: 6
Density: 7,850

You get

Diameter unit: Mm
Length unit: M
Inner diameter: 90
Outer diameter m: 0.1

Buying, cutting, or hanging a hollow pipe without knowing its mass is how crews overload a van, undersize a hoist, or overpay for freight. Outer diameter and wall thickness set the annular metal or plastic that actually exists; length and material density turn that ring into kilograms. This pipe weight calculator takes those four quantities, converts millimetre diameters and metre lengths into SI, and applies the hollow-cylinder identity: material volume equals pi times wall thickness times the quantity outer diameter minus wall thickness, times length. Mass is density times that volume. The number you get is the weight of the pipe wall itself—not the water or gas that might fill the bore, and not a solid round bar of the same outer size.

How hollow pipe weight is calculated from outer diameter, wall, length, and density

A hollow circular pipe is a right circular cylinder with a coaxial cylindrical bore. After outer diameter, wall thickness, and length are expressed in metres, the inner diameter is the outer diameter minus twice the wall thickness. That inner diameter must stay strictly positive: if wall thickness is half the outer diameter the bore collapses to a line, and if wall thickness is larger the geometry is impossible.

The material volume is the difference of two solid-cylinder volumes, pi times outer radius squared times length minus pi times inner radius squared times length. Algebra simplifies that difference to a form estimators memorize: volume equals pi times wall thickness times outer diameter minus wall thickness, times length. Multiplying by material density in kilograms per cubic metre yields the total mass in kilograms, which this calculator also reports in pounds and as mass per metre of run.

The identity is exact for a perfect annulus; it does not add mill tolerances, weld beads, coatings, or threads. Density is a material property you supply: mild steel is commonly taken as seven thousand eight hundred fifty kilograms per cubic metre, aluminum about two thousand seven hundred, copper about eight thousand nine hundred sixty, and many PVCs near one thousand four hundred.

Because diameter and thickness usually appear on mill certificates in millimetres while cut length is in metres, the calculator converts those families separately rather than forcing every number into one unit.

Where a pipe weight calculator earns its keep

Fabricators, mechanical contractors, and warehouse teams reach for a pipe weight calculator when a cut list must become a shipping mass or a hanger load before the truck or the hoist is booked. Steel stockholders price by the kilogram; converting outer diameter, schedule wall, and length into mass is the step that turns a catalogue line into an invoice. Structural and piping engineers comparing carbon steel against aluminum or plastic for the same envelope need an apples-to-apples wall mass, not a volume and a separate density lookup in another tab.

This landing is intentionally not the weight of water filling a pipe, which is a different search and a different capability: hangers that carry a flooded line still need the metal mass on top of the fluid mass, and mixing those two numbers is a classic estimating error. It is also not a solid-bar weight calculator, which uses the full outer disk instead of the annulus, and not a pipe-volume tool that stops at cubic metres without density.

Curriculum authors and exam writers ask for the mass of a hollow steel tube from outer diameter, thickness, length, and density; a deterministic oracle marks those items without mixed-unit surprises. Invalid input is not billed. Pin the rounded weight fields in tests, keep requests small, and you get reproducible pipe weights for ERP plugins, shop-floor tablets, and edge workers without standing up a materials database of your own.

What you can do with it

Cut lists to shipping mass

Turn mill OD, wall thickness, and cut length into kilograms and pounds so a spool, crate, or truck load is booked against real metal mass, not a guess from a dog-eared table.

Material takeoff and mill invoices

Convert a purchase of carbon steel, aluminum, copper, or plastic pipe into billed kilograms using the density on the mill certificate instead of a solid-bar formula that overstates mass.

FAQ

How is hollow pipe weight calculated?

Inner diameter is outer diameter minus twice the wall thickness. Material volume is π × t × (OD − t) × L after converting to metres. Total weight is that volume times density in kg/m³. The response also reports pounds and mass per metre.

What happens if wall thickness is half the outer diameter or more?

When wall thickness equals or exceeds half the outer diameter the bore vanishes, so the geometry is not a hollow pipe. Validation failures are not billed.

Which units should I use for diameter, wall, and length?

Density is always kilograms per cubic metre. You can switch either linear unit to m, cm, mm, in, or ft.

Is this the weight of water inside the pipe?

No. This calculator returns the mass of the pipe wall. The mass of water filling the bore is a different search intent; add that fluid mass separately if you are sizing hangers for a flooded line.

What density should I use for steel, aluminum, copper or PVC?

Mild steel is commonly taken as 7850 kg/m³, aluminum about 2700, copper about 8960 and many PVCs near 1400. Enter the density of your own material in kilograms per cubic metre.

Related tools

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/build/pipe-weight

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/build/pipe-weight \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"outer_diameter":100,"wall_thickness":5,"length":6,"density":7850}'

const res = await fetch("https://api.kit.forhosting.com/build/pipe-weight", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "outer_diameter": 100,
    "wall_thickness": 5,
    "length": 6,
    "density": 7850
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/build/pipe-weight",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "outer_diameter": 100,
    "wall_thickness": 5,
    "length": 6,
    "density": 7850
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/build/pipe-weight", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"outer_diameter":100,"wall_thickness":5,"length":6,"density":7850}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"outer_diameter":100,"wall_thickness":5,"length":6,"density":7850}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/build/pipe-weight", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "outer_diameter": 100,
  "wall_thickness": 5,
  "length": 6,
  "density": 7850
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "build.pipe_weight",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Technical notes

When wall thickness equals or exceeds half the outer diameter the bore disappears, so the task fails with invalid_input instead of treating a solid rod as a pipe.

Input contract, units, and the half-diameter error

A worked check: one hundred millimetres outer diameter, five millimetres wall, six metres length, and steel density seven thousand eight hundred fifty kilograms per cubic metre produces an inner diameter of ninety millimetres and a total mass of about seventy point three kilograms. Send four required finite numbers. outer_diameter is the outside diameter of the pipe and must be strictly positive. wall_thickness is the radial wall and must be strictly positive and strictly less than half the outer diameter; the two share diameter_unit. length is the axial cut length and must be strictly positive. density is the material mass density in kilograms per cubic metre and must be strictly positive. Optional diameter_unit applies to both outer_diameter and wall_thickness and accepts m, cm, mm, in, or ft, defaulting to millimetres because metric pipe is quoted that way. Optional length_unit accepts the same five tokens and defaults to metres. Aliases such as od, diameter, t, wall, L, and rho are accepted on the wire so mill spreadsheets do not have to rename columns. Missing fields, empty strings, non-finite values, non-positive dimensions or density, and unrecognized units fail with invalid_input and a message that names the field. On success the body echoes the cleaned inputs and units, reports inner_diameter in the same unit as the outer diameter, restates every linear quantity in metres, and returns material_volume_m3, weight_kg, weight_lb, weight_per_m_kg, and weight_per_ft_lb, plus the formula string and a short message. Successful API calls use the published base of $0.002 per item; validation failures are not billed. Numeric strings are accepted the same as JSON numbers so a form field and a JSON body behave alike.

Integration use cases

Hanger, hoist, and exam checks

Size hangers and hoists to the pipe wall mass, then add fluid weight separately, or mark hollow-tube mass items in a course with the same contract the public widget uses.

Technical questions

What does the pipe weight calculator cost?

The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.

Read the full KIT documentation →

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