🪈Pipe Calculator
The Pipe Calculator Toolset

Pipe Calculators, One Engine

20 tools covering the pipe jobs you actually do: weight for trucking and lifting, volume for hydro testing, pressure rating for process lines, bends and cut lengths for fabrication, slope for gravity runs, spacing for hangers, and cost for the takeoff sheet. Every calculator reads the same NPS table, the same Schedule walls and the same material densities — so the numbers can never quietly disagree with each other.

Open the Weight Calculator Browse by Category
Free, no sign-up Live on every keystroke Imperial & metric
Industrial steel pipe runs and valves inside a process plantOne toolset for the whole life of a pipePhoto: Unsplash
Live on every keystroke
Imperial & metric
Standard NPS & Schedule
18+ material densities
No sign-up, no caps
About the Toolset

20 Tools, One Shared Dataset

A pipe project asks the same handful of questions in a different order every time: how heavy is it, how much does it hold, what pressure will it take, how long is the blank, how much fall does the run need, how far apart do the hangers go, and what will it cost. Most sites answer one of those questions and leave you to find the rest elsewhere — which is where estimates go wrong, because a weight from one site and a pressure from another were never computed from the same dimensions in the first place. The Pipe Calculator toolset is built the other way around: 20 calculators that all read from one dataset.

That shared dataset is the design decision everything else follows. The outer-diameter behind every NPS preset comes from the same ASME B36.10M dimension table whether the weight calculator fills it, the volume calculator derives a bore from it, or the pressure tool applies a wall to it. The densities in the weight engine are the same ones the cost tool multiplies into an order weight. Switch from the bend calculator to the support spacing tool mid-job and you are still working on the same pipe — the numbers carry over because the definitions do.

The toolset is also opinionated about who it serves. A pipefitter hanging a header wants the support spacing answer, not an essay. An estimator wants an order weight that survives contact with the supplier's quote. A homeowner wants to know whether one railing run is a one-person job. So each tool does one calculation with the inputs you would actually have on site — a tape measure, a schedule stamp, a material — and shows the formula it used, so every result can be checked rather than trusted.

Everything on this page runs in your browser, on your device, in real time. Nothing you type is uploaded, stored, or attached to an identity, and there is no premium tier hiding better numbers behind a subscription. Pick the question you are standing in front of from the categories below, and open the tool that answers it.

Browse by Job

The Calculators, Categorized

Four groups, ordered the way a job unfolds — reference first, then what the pipe carries, then how it gets built and hung, and finally what it costs. Each card opens the live tool; each category intro explains when its tools are the right ones to reach for.

01

Weight, Size & Reference

This is where most visits start and where the dataset lives. The pipe weight calculator is the engine of the whole site: pick an NPS, a Schedule and a material, and it returns weight per foot, total weight and volume in a single keystroke. The steel weight chart pre-tabulates the same arithmetic for every standard size so you can look a figure up without typing anything, and the pipe dimension calculator decodes the nominal naming system into real OD, ID, wall and circumference — the numbers every other tool on this page quietly depends on. The pipe size calculator works the same dataset in reverse: give it a flow rate and a target velocity, and it returns the smallest standard pipe that carries it, while the square-tube weight tool extends the density math to box sections. If you are checking a quote, sizing a truckload, or just trying to answer how heavy is this stick, start here.

Reach for these when…

  • You need the weight of a pipe, a bundle, or a whole order
  • You want lb/ft for a standard size without typing anything
  • A drawing uses NPS or DN and you need real inches or millimetres
  • You know the flow rate and need the smallest pipe that carries it
📐

Pipe Dimension Calculator

NPS, DN, OD, ID, wall and circumference in one converter — calculate pipe outside diameter from schedule with the formulas shown.

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📏

Pipe Size Calculator

Find the right pipe diameter from flow rate and velocity — GPM or CFM in, nearest NPS out, with Sch 40/80 velocity check.

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🟦

Square Tube Weight Calculator

Weight of square and rectangular hollow sections from side, wall and length — MS, stainless and aluminum in lb/ft and kg/m.

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🪶

Plastic Pipe Weight Calculator

Weight per foot for PVC Sch 40 and 80, CPVC, HDPE and PEX — plus buried pipe buoyancy check and deflection, compared with steel and ductile iron.

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02

Capacity, Pressure & Process

Once a line is hanging, the questions change from what does it weigh to what can it carry. The volume calculator computes both sides of a pipe's life — the metal volume that sets the weight, and the bore capacity that sets how much water, product or test medium it holds. The flow rate calculator turns that capacity into motion: velocity, GPM and the maximum flow a size can pass. The pressure drop calculator prices the friction you pay for every foot of run with Darcy-Weisbach, and the gravity flow calculator applies the Manning equation to sewers, storm drains and culverts that run partially full. The pressure rating tool applies Barlow's formula to the same geometry, and the insulation calculator closes the thermal side. Two newer tools round out the physics: the compressed air calculator runs the gas-side math where liquids' formulas would lie, and the Reynolds number calculator rules on laminar versus turbulent before any friction factor is picked. Together they cover what the pipe carries from both ends — pressure-driven and gravity-driven.

Reach for these when…

  • You are hydro testing and need fill volume plus filled weight
  • A process line needs velocity, GPM or a friction-loss check
  • A sewer, drain or culvert needs a gravity capacity figure
  • Compressed-air mains need CFM and drop sized on gas physics
🛢️

Pipe Volume Calculator

Bore capacity of any pipe in gallons, litres, m³ and ft³ — water volume per foot for NPS 1/8–36, plus filled weight.

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💨

Pipe Flow Rate Calculator

Flow rate, velocity and max flow through a pipe from diameter, pressure or velocity — water GPM and LPM in one tool.

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📉

Pipe Pressure Drop Calculator

Darcy-Weisbach pressure drop and friction loss per 100 ft for steel, PVC and copper — Reynolds number and fittings K included.

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🔄

GPM to PSI Calculator

Convert GPM to PSI pressure drop or calculate GPM from PSI and pipe size — Hazen-Williams C-factors, run length and material in one live tool.

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🔧

Fittings Pressure Drop Calculator

Equivalent length and friction loss for elbows, tees, valves and strainers — K-factors, L/D ratios and total fitting pressure drop in psi.

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🌊

Gravity Pipe Flow Calculator

Manning equation flow for gravity sewers, storm drains and culverts — full or partially full pipe, slope, n-values and capacity.

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🛡️

Pipe Wall Thickness Calculator

ASME B31.3 wall thickness from design pressure — hoop stress, external pressure, carbon steel to ductile iron, and Sch 10-160 schedule matching.

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🔥

Pipe Insulation Calculator

Surface area, insulation volume and heat loss for any pipe run — π·D·L math, per-foot NPS tables and thickness comparison.

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🌬️

Air Flow Calculator

CFM flow and pressure drop for compressed air lines — size shop mains and branch drops, check velocity and friction loss per 100 ft.

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🌀

Reynolds Number Calculator

Reynolds number for any pipe flow from size, velocity and fluid — water, air and oil presets with a laminar or turbulent verdict.

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03

Fabrication & Installation

These tools translate the weight numbers into work on the floor and in the air. The bend calculator turns a bend angle and centerline radius into bend allowance, setback and cut length, so the blank you cut is the spool you wanted. The slope calculator converts between inches-per-foot, percent and degrees for gravity lines — drain, gas or condensate — and totals the fall across a run. The support spacing calculator takes your pipe's weight and size and returns recommended hanger spacing aligned with MSS SP-58 and ASME B31 practice. The thermal expansion calculator covers the load nobody sees until it binds: how far a hot line grows, how big the compensation loop must be, and whether the anchors survive the stress. Together they cover the gap between a pile of straight pipe and a system that actually holds itself up.

Reach for these when…

  • You are cutting blanks for bends and spools
  • A drain or gravity line needs its fall specified
  • Hangers and supports need spacing before the run goes up
  • A hot line needs growth, loops or stress checked
🌡️

Thermal Expansion Calculator

Pipe growth from ΔL = α·L·ΔT for steel, copper, PVC and HDPE — expansion loop sizing, thermal stress and restraint guidance.

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04

Cost & Procurement

Steel is bought by the pound, plastic by the stick, and both by the mistake you avoid before signing. The cost calculator takes the output of the weight engine — order weight — and multiplies it by your material price, length, quantity and waste allowance to produce a budget you can defend in a meeting. It is deliberately simple: the goal is not to replace your supplier's quote but to arrive at one, with a number close enough that a quote far from it is a question worth asking. Pair it with the weight chart and you can sanity-check any takeoff in the time it takes to read the email.

Reach for these when…

  • You are pricing an order before the quotes come back
  • You want a material-plus-weight budget for a run
  • A supplier's number looks off and you want a baseline
One Dataset, Proven

One Pipe, Four Tools, Zero Disagreement

The test of a shared dataset is simple: run the same pipe through every tool and the story has to stay consistent. Here is 6" NPS Sch 40 carbon steel — the most common pipe in the yard — through the four tools it meets most often. Every figure traces back to the same 6.625" OD and 0.280" wall, and you can reproduce each one in the tool it names.

STEP 1

Weight calculator

18.97 lb/ft of steel

6" NPS, Sch 40 (t = 0.280"), carbon steel at 7.85 g/cm³ — the annulus math in one keystroke, and the number every other tool builds on.

STEP 2

Volume calculator

≈1.50 gal/ft of bore

The same 6.625" OD and 0.280" wall give a 6.065" ID, so a full stick of pipe carries about a gallon and a half of water per foot — 12.5 lb/ft you add before a hydro test.

STEP 3

Pressure rating tool

Burst-basis pressure from Barlow

P = 2·S·t/D turns the same wall into a pressure figure; the tool refines it with your material strength and the safety factor your spec calls for.

STEP 4

Cost calculator

Order weight × your rate

Twenty sticks at 21 ft is 420 ft ≈ 7,967 lb; at a quoted $/lb the budget appears before the supplier's does — and disagreements get caught early.

A run of large diameter steel pipe on supports at an industrial siteSame dimensions, every tool, every timePhoto: Unsplash

Why This Matters on a Real Job

The classic failure is not one bad number — it is two good numbers that were never talking. A hanger layout computed from a heavier schedule than the pipe actually ordered. A hydro test planned with the metal weight but not the water. A freight quote built on a density from the wrong alloy family. Each one is an honest mistake made across tool boundaries.

Sharing one dataset is the structural fix. The Schedule wall that set your weight also sets your pressure figure; the density that priced your order also weighs your truck. When the definitions are shared, the mistakes get caught by arithmetic instead of by the crew.

See the NPS & Schedule data
Quick Router

Which Tool Answers Your Question?

Find the question you are holding, follow the row, open the tool. Every calculator is one click from this table — and back to the weight engine when the next question starts.

If you need to know…
Open…
You get…
How heavy is this stick — or this truckload?
lb/ft, kg/m and total weight
What is the lb/ft for a standard size, no typing?
Tabulated weights, NPS 1/8–36
What is 6-inch pipe in millimetres, really?
📐Pipe Dimension Calculator
OD, ID, wall and circumference
What size pipe carries 30 GPM at 6 ft/s?
📏Pipe Size Calculator
Diameter and nearest NPS
How much water fills the line for a test?
🛢️Pipe Volume Calculator
Bore capacity and filled weight
What velocity and GPM does this line run?
💨Pipe Flow Rate Calculator
Flow, velocity and max flow
How much pressure do I lose per 100 ft?
📉Pipe Pressure Drop Calculator
Darcy-Weisbach friction loss
What can a half-full sewer at 1% carry?
🌊Gravity Pipe Flow Calculator
Manning flow, full or partial
Will this schedule hold my working pressure?
Barlow pressure by material
How much wrap and insulation does the run need?
🔥Pipe Insulation Calculator
Coverage area and thickness
How long is the blank for a 45° bend?
Bend allowance and cut length
How much fall across a 40 ft drain run?
Grade, percent and total drop
How far apart can the hangers be?
Spacing by size and schedule
How much CFM moves through this air main?
🌬️Air Flow Calculator
CFM, velocity and pressure drop
How much will a hot line grow — and does the loop cover it?
🌡️Thermal Expansion Calculator
Growth, loop size and stress
Is this line laminar or turbulent?
🌀Reynolds Number Calculator
Re, regime verdict and friction factor
How many GPM will this PSI and pipe size deliver?
🔄GPM to PSI Calculator
Hazen-Williams flow or pressure drop
What do the fittings cost in friction?
🔧Fittings Pressure Drop Calculator
K-factors and equivalent length
How thick must the wall be for this pressure?
🛡️Pipe Wall Thickness Calculator
B31.3 thickness and schedule
What does PVC pipe weigh — and will it float?
🪶Plastic Pipe Weight Calculator
Weight, buoyancy and deflection
What does a square tube weigh per foot?
🟦Square Tube Weight Calculator
Box section lb/ft and kg/m
What will the whole order cost?
Budget from weight × rate
The Core Tool

Inside the Pipe Weight Calculator

The weight calculator is where the whole toolset begins, and its inputs are the vocabulary every other tool assumes you know. Six settings do all the work — each one mapped to a decision you make on the job, none of them hidden behind an account or a paywall.

NPS presets, 1/8" to 36"

One click fills the exact ASME B36.10M outer diameter — no lookup table, no typing errors on the number everything else depends on.

Schedule walls, Sch 10 to 160

Selecting a Schedule fills the matching wall thickness for the size, so 'Sch 40' means the right 0.280" at 6 inch and the right 0.465" at 12 inch.

18+ material densities

Carbon and mild steel, stainless 304/316, aluminum, copper, brass, PVC, HDPE and more — plus a custom density field fed straight from a mill certificate.

Imperial and metric together

Inputs, presets and results switch as a system, and every result shows its twin — lb/ft beside kg/m — so cross-border quotes never need a second conversion.

Quantity multiplier

Set the number of sticks and the engine returns the bundle total, the freight-relevant figure that turns one weight into an order.

Live on every keystroke

No calculate button, no sign-up, no result caps. Change the Schedule and watch the weight, volume and cost move before your finger leaves the key.

From Dimensions to a Defensible Number

Under the hood the engine runs one formula and a few conversions: the annulus cross-section from OD and ID, volume from the length you entered, density converted to weight, and the quantity multiplier on top. Enter any two of the three dimensions and it derives the third — type the OD and the wall, and the ID appears; type the OD and the ID, and the wall it implies does too.

The outputs are organized the way takeoffs are read: linear density first, because it is independent of length; then per-stick weight; then the quantity total that books the truck. Volume sits beside them in the same unit system, ready for the fill-weight questions the volume calculator picks up.

Walk the full how-to
A technician measuring steel pipe with calipers before running the calculatorTwo dimensions in, every number outPhoto: Unsplash
Pipe reference charts and a laptop with the pipe calculator open on a workbenchEvery tool has a guide behind itPhoto: Unsplash
Tools + Guides

Not Sure Which Number to Trust? Read the Guide.

Every calculator on this page has a matching set of guides that explain the ideas behind its inputs — what a Schedule actually selects, why PVC floats where steel sinks, where the 10.68 rule comes from, and how to check a supplier's quote against your own takeoff.

The guides and the tools are written as a pair: the reading explains why a number moves, the tool shows how far it moves. If a result ever surprises you, the guide library is the fastest way to find out whether the surprise is the math or the measurement.

Browse the guide library

Questions About the Toolset

Are all of the calculators free to use?▼

Yes — every tool on this page is free, requires no account, and has no usage caps or paywalled fields. The site is a reference toolset, not a lead-generation funnel: nothing gates a result, and no result is emailed to anyone.

Do the calculators share inputs with each other?▼

They share the dataset, not a session. Each tool is standalone — you will re-enter the size on a new tool — but every tool reads the same NPS table, the same Schedule walls and the same material densities, so a figure from one tool is always consistent with the others. There is no second copy of the data to drift out of date.

Where do the numbers come from?▼

Outer diameters and Schedule wall thicknesses follow the ASME B36.10M dimension tables that govern carbon steel pipe, and material densities are handbook averages for each alloy family — carbon steel at 7.85 g/cm³, 304 stainless at 7.93, PVC at 1.45, and so on. The weight chart page shows the full tabulation, and each tool shows the formula it applies so you can verify any result by hand.

Which calculator should I start with?▼

The pipe weight calculator. It is the hub: the weight figure it produces feeds cost estimates, payload planning, support spacing and hydro-test planning. Start with the size and material you have, read the linear density, and then follow the links from this page to the tool that answers the next question about that same pipe.

Can I work in metric only?▼

Yes. Switch the unit system and the presets, inputs and outputs all move together — millimetres for OD, wall and length, kilograms for weight, kg/m for linear density. The imperial equivalents stay visible on every result, so a metric run can still be checked against an imperial chart without any manual conversion.

Can I request a calculator that is not here yet?▼

Please do. Send the calculation you keep doing by hand — what inputs you start from, what result you need out — through the contact page. Requests that describe a real, repeated field problem go to the top of the queue, and the toolset grows the same way the guide library does: from questions that were worth writing down.

Run Your First Pipe Now

Pick an NPS, a Schedule, a material, and a length — the engine returns weight, linear density and volume in one keystroke. Then set a quantity for the full-truck total, and follow this page to the tool that answers the next question. Free, private, and instant.

Open the Pipe Weight Calculator Read the Guides First