Pipe Sizing Chart and Different Types

To begin with, a pipe is a tubular section or hollow cylinder, usually but not necessarily of circular cross-section, used mainly to convey substances that can flow liquids and gases (fluids), slurries, powders, and masses of small solids. In fluid mechanics, the flow of fluid in a pipe is a type of liquid flow within a closed conduit, such as a pipe or tube (skip straight to the Pipe Sizing Chart).

A pipe diameter often specifies a pipe with a constant outer diameter (OD) and a schedule that specifies the thickness, depending on the applicable standard to which it is constructed. The internal diameter (ID), outside diameter (OD), and wall thickness are the most common measurements used to specify tubes.

PIPE SIZING Chart : Nominal Pipe sizes vs Outside diameter vs inside diameter vs wall thickness
PIPE SIZING : Nominal Pipe sizes vs Outside diameter vs inside diameter vs wall thickness

Although there are similar requirements for tubes used in particular industries, they are frequently fabricated to custom sizes and a wider variety of diameters and tolerances. For manufacturing pipe and tubing, many industrial and governmental standards exist. Non-circular pipes, such as square or rectangular tubing, are also sometimes referred to as “tubes.” “tube” is more often used in the United States, while “pipe” is more frequently used in most of the rest of the world.

Jump right into the Frequently Asked Questions

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Table of content: Pipe Sizing Chart

Pipe Sizing Chart

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Pipe Sizing Chart (1/8 inch–24 inch Nominal Bores)

Nominal BoreNominal DiameterOuter DiameterSchedule 40 Wall ThicknessSchedule 40 WeightSchedule 40 Internal DiameterSchedule 80 Wall ThicknessSchedule 80 WeightSchedule 80 Internal Diameter
0.125inch 0.32 cm0.236inch 0.6 cm0.405inch 1.029 cm0.068inch 0.173 cm0.37kg/m 2.78lb/ft0.269inch 0.684 cm0.095inch 0.241 cm0.47kg/m 3.4lb/ft0.215inch 0.584 cm
0.25inch 0.625cm0.315inch 0.8 cm0.54inch 1.372cm0.088inch 0.224 cm0.63kg/m  4.6lb/ft0.364inch 0.922cm0.119inch 0.302 cm0.8kg/m    5.8lb/ft0.302inch 0.766 cm
3/8 inch   0.95 cm0.394inch  1 cm0.675inch 1.715cm0.09 inch 0.231 cm0.84kg/m   6.08lb/ft0.493inch 1.248cm 0.126inch 0.32 cm 1.1kg/m   8lb/ft0.423inch 1.07 cm
1/2 inch   1.27 cm0.59inch 1.5 cm0.840inch 2.134cm 0.109inch 0.277 cm 1.27kg/m   9.2lb/ft0.62inch 1.576cm0.147 inch 0.373 cm 1.62kg/m   11.7lb/ft 0.546inch 1.384 cm
3/4 inch   1.905cm0.787inch  2 cm1.05inch 2.667cm 0.113inch 0.287 cm1.69kg/m  12.22lb/ft 0.824inch 2.096 cm0.154 inch 0.391 cm2.2kg/m     16lb/ft 0.742inch 1.888 cm
1 inch       2.54 cm0.984inch 2.5 cm1.315inch 3.34 cm 0.133inch 0.338 cm 2.5kg/m    18.08lb/ft1.049inch 2.664cm 0.179inch 0.455 cm 3.24kg/m   23.4lb/ft0.957inch 2.43 cm
1-1/4inch 3.175 cm1.26inch   3.2 cm1.66inch 4.216cm 0.14inch 0.356 cm 3.39kg/m   24.5lb/ft 1.38inch 3.508cm 0.191inch 0.485 cm4.47kg/m   32.3lb/ft 1.278inch 3.25 cm
1-1/2 inch          3.81cm1.574inch  4 cm1.9inch 4.826cm0.145inch 0.368 cm4.05kg/m   29.3lb/ft 1.61inch 4.094cm 0.2 inch 0.508 cm 5.41kg/m   39.1lb/ft 1.5inch 3.814 cm
2inch 5.08 cm1.97inch     5 cm2.375inch 6.033cm 0.154inch 0.391 cm5.44kg/m   39.3lb/ft2.067inch 5.248 cm0.218inch 0.554 cm7.48kg/m   54.1lb/ft 1.94inch 4.922 cm
2.5inch    6.35 cm2.56inch 6.5 cm2.875inch 7.302cm 0.203inch 0.516 cm8.63kg/m   62.4lb/ft 2.469inch 6.268 cm0.276inch 0.701 cm11.41kg/m   82.5lb/ft 2.32inch 5.898 cm
3inch       7.62 cm3.45inch     8 cm3.5inch 8.89cm 0.216inch 0.549cm11.29kg/m   81.7lb/ft 3.068inch 7.792 cm 0.3 inch 0.762 cm15.27kg/m   110.4lb/ft 2.9 inch 7.366 cm
3.5inch    8.89cm3.54inch     9 cm4inch 10.16cm 0.226inch 0.574 cm13.57kg/m   98.2lb/ft 3.548inch 9.012 cm 0.318inch 0.808 cm18.64kg/m   143.8lb/ft3.36inch 8.54cm
4inch 10.16cm3.937inch 10 cm4.5inch  11.43 cm 0.237inch 0.602 cm16.08kg/m   116.3lb/ft 4.02inch 10.22 cm0.337 inch 0.856 cm22.32kg/m   161.4lb/ft 3.83inch 9.72cm
5inch   12.7cm   4.921inch 12.5 cm5.56inch 14.13cm 0.258inch 0.655cm21.77kg/m   157.5lb/ft 5.047inch 12.82 cm 0.375inch 0.953cm30.97kg/m   224lb/ft 4.81inch 12.22cm
6inch  15.24 cm5.91inch  15 cm6.625inch 16.82cm 0.28inch 0.711cm28.26kg/m   204.4lb/ft 6.07 inch 15.4 cm 0.432inch 1.1 cm42.56kg/m   307.8lb/ft 5.76inch 14.64cm
8inch   20.32cm7.87inch  20 cm8.625inch 21.9cm 0.322inch 0.818 cm 42.55kg/m   307.8lb/ft 7.981inch 20.27cm 0.5 inch 1.27 cm 64.64kg/m   467.5lb/ft7.625inch 19.37 cm
9inch   22.86cm8.86inch  22.5 cm9.625inch 24.45cm0.342inch 0.869 cm50.54kg/m   365.6lb/ft8.94inch 22.71cm0.5inch 1.27 cm72.6kg/m     525.1lb/ft8.625inch 21.91 cm
10inch    25.4cm9.842inch 25 cm10.75inch 27.3 cm0.365inch 0.927 cm60.2 kg/m    435.4lb/ft10.02inch 25.45 cm0.59inch 1.509 cm95.98kg/m   694.2lb/ft9.56inch 24.28cm
11inch   27.94cm10.826inch   27.5 cm11.75inch 29.85cm0.375inch 0.953 cm67.91kg/m   491.2lb/ft11 inch 27.94 cm0.5 inch 1.27 cm89.51kg/m   647.4lb/ft10.75inch 27.31cm
12inch   30.48cm11.81inch 30 cm12.75inch 32.38cm 0.375inch 0.953 cm 73.86kg/m 534.2lb/ft12 inch 30.47 cm0.688inch 1.748 cm 132.05kg/m   955.1lb/ft 11.38inch 28.88cm
14inch   35.56cm13.76inch 35 cm14inch 35.56cm 0.438inch 1.113 cm 94.55kg/m   683.9lb/ft13.12inch 33.33cm0.75 inch 1.905 cm158.11kg/m   1143.6lb/ft12.5inch 31.75 cm
16inch   40.64cm15.75inch 40 cm16inch 40.64cm 0.5inch 1.27 cm123.31kg/m   891.9lb/ft15 inch 38.1 cm 0.844inch 2.14 cm203.54kg/m   1472.2lb/ft14.31inch 36.35cm
18inch   45.72cm17.72inch 45 cm18inch 45.7 cm 0.562inch 1.427 cm155.81kg/m   1127lb/ft16.9 inch 42.85 cm 0.938inch 2.383 cm254.57kg/m   1841.3lb/ft16.12inch 40.934cm
20inch   50.8cm19.7inch  50 cm20inch 50.8 cm0.594inch 1.509 cm183.43kg/m   1326.7lb/ft18.81 inch 47.78 cm1.031inch 2.619 cm311.19kg/m   2250.8lb/ft17.94inch 45.56cm
22inch   55.88cm21.65inch 55 cm22 inch 55.9 cm 0.375inch 0.953 cm229.14kg/m  1657.4lb/ft   21.25 inch 53.99 cm 1.125inch 2.858 cm373.85kg/m   2704.1lb/ft 19.75inch 50.18cm
24inch   60.96cm23.62inch 60 cm24 ich   61 cm 0.688inch 1.748 cm255.43kg/m   1847.5lb/ft22.62 inch 57.5 cm1.219inch 3.096cm442.11kg/m   3197.8lb/ft21.56inch 54.808cm

Pipe Sizing Chart (26inch -48inch Nominal Bores)

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Nominal BoreNominal DiameterOuter DiameterStandard ThicknessStandard Thickness WeightStandard Thickness Internal DiameterExtra Strong ThicknessExtra Strong Thickness WeightExtra Strong Thickness Internal Diameter
26inch 66.04cm25.6inch 65cm26 inch 66.0 cm0.375inch 0.953 cm152.88kg/m 1105.8lb/ft25.25inch 64.09 cm0.5 inch 1.27 cm202.74kg/m   1466.4lb/ft25inch 63.46 cm
28inch    71.12cm27.6inch 70cm28 inch 71.1 cm0.375inch 0.953 cm164.86kg/m   1192.4lb/ft27.25inch 69.19 cm0.5 inch 1.27 cm218.71kg/m   1581.9lb/ft27 inch 68.56 mm
30inch    76.2cm29.5inch 75cm30 inch 76.2 cm 0.375inch 0.953 cm 176.85kg/m   1279.2lb/ft29.25 inch 74.29 cm0.5 inch 1.27 cm234.68kg/m   1697.4lb/ft29 inch 73.66 cm
32inch    81.28cm31.5inch 80cm32 inch 81.3 cm 0.375inch 0.953 cm 188.83kg/m   1365.8lb/ft31.25 inch 79.39 cm 0.5 inch 1.27 cm250.65kg/m   1813lb/ft 31inch 78.76 cm
34inch    86.36cm33.5inch 85cm34 inch 86.4 cm  0.375inch 0.953 cm 200.82kg/m   1452.5lb/ft33.25 inch 84.49 cm 0.5 inch 1.27 cm266.63kg/m   1928.5lb/ft33inch 83.86 cm
36inch    91.44cm35.4inch 90cm36 inch 91.4 cm 0.375inch 0.953 cm 212.57kg/m   1537.5lb/ft35.25 inch 89.49 cm0.5 inch 1.27 cm282.29kg/m   2041.8lb/ft 35inch 88.86 cm
42inch    106.7cm41.3inch 105cm42 inch 106.7cm   0.375inch 0.953 cm248.53kg/m   1797.6lb/ft41.25 inch 104.79cm0.5 inch 1.27 cm330.21kg/m   2388.441inch 104.2 cm
48inch    121.9cm47.2inch 120cm48 inch 121.9cm 0.375inch 0.953 cm 284.25kg/m   2056lb/ft47.25 inch 119.99cm0.5 inch 1.27 cm377.81kg/m   2732.6lb/ft47inch 119.4 cm

How to choose the right pipe size

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Although it can be a little perplexing, anyone can learn how to measure pipe size. Get whether you need to measure the outside or pipe inner diameter before measuring with a ruler or tape to determine the correct size. The measurement must then be converted to the nominal pipe size PVC, which is what the pipe will be referred to as in the store. Knowing how to measure pipe size is crucial for plumbing and construction tasks.

Measuring the Right Diameter

Determine whether your correct pipe has “male” or “female” threads, or whether it is threadless. The tiny grooves on the ends of some pipes are called threads, which aid in fitting the pipes. In contrast to female threads on the inside of the pipe, male threads are located there.

If the diameter pipe contains male threads or none measure the outside diameter. The pipe’s overall outside diameter is measured from outside edge to outside edge. Use a flexible measuring tape to measure the pipe’s circumference to find it. Pi, or approximately 3.14159, is the circumference divided.
If the pipe contains female threads, measure the interior diameter. Without accounting for the thickness of the pipe walls, that measurement represents the pipe’s midway distance.

Converting to Nominal Pipe Size PVC

If your diameter is less than 14 inches, convert it to a nominal size (360 mm). You don’t need to convert it if the diameter is 14 inches (360 mm) or greater because it already matches the nominal diameter.
Determine whether you must convert to NPS or DN. If you are in North America, convert to Nominal Pipe Size (NPS), or if you are using the metric system, convert to Diameter Nominal (DN).

Frequently Asked Questions

Is nominal pipe size OD or ID?

Nominal pipe size refers to only the pipe inner diameter/outside diameter (OD) of a pipe, making it somewhat vague.

What does Sch 40 mean?

SCH 40 is the same wall thickness as the previously used value.

Which is the stronger schedule 40 or 80?

Schedule 40 PVC pipe is strong, rigid, and can handle pressure applications. For jobs that require higher pressure, though, schedule 80 pipe is better suited.

Is Schedule 40 or 80 thicker?

Schedule 40 pipe has thinner walls, so it is best for relatively low water pressure applications. Schedule 80 pipe has thicker walls and can withstand higher PSI (pounds per square inch).

How do I choose a pipe schedule?

Measure the outside diameter and the wall thickness of the pipe. Refer to the pipe schedule chart and find the outside diameter. Find the wall thickness in the corresponding column.

When Did Pipe Scheduling Start?

The Iron Pipe Size (IPS) System introduced steam pipe schedules and acceptable pipe sizes. This method of sizing created numbers to specify the rough pipe dimensions. Because of manufacturing tolerances, pipe manufacturers produced piping with a comparatively uniform thickness and schedule designations.

However, manufacturers began making pipes with thicker inner walls as pipe use increased and piping was required to handle higher pressures. Manufacturers categorized pipes into three major pipe sizes to represent the early thickness discrepancies:

  • Standard weight
  • Extra-strong
  • Double extra-strong

There was eventually a need to consider different industries, various piping environments, and fluctuating pipe temperatures as mass production began to produce an increasing number of piping possibilities. Because of this, the American Standards Association developed steam pipe schedule numbers in the late 1920s to divide measurements of pipe wall thickness into smaller units.

How Do Pipe Sizes Work Today?

Today, there are two pipe classifications you can use to identify your pipe’s sizing quickly:

  1. Nominal Pipe Size
  2. Pipe Schedule

These pipe velocities help you estimate the full size of your pipe measurements, so you can safely install piping systems, pipe supports, and pipe layouts.

The American Standard Institute and the American Society of Mechanical Engineers (ASME) assign pipe schedule numbers to provide a uniform set of pipe measurements. They show the pipe’s nominal wall thickness. Schedule 40 and Schedule 80 are two of the most used pipe schedule numbers.

What Is Nominal Pipe Size?

In North America, nominal pipe size is the standard for identifying pipe sizes. Outside North America, pipes are identified by nominal diameter, which approximately equates to the pipe’s outer diameter (OD) in millimeters.

Note that an NPS below 14 approximately refers to the diameter of a pipe measured from the center of the wall material to the opposing side center of the wall material, whereas an NPS of 14 or greater matches the outside diameter of the pipe precisely.

It is important to note that the difference in total pressure factors between two ends of a pipe is known as pressure drop. Pressure drop, also known as pressure loss, happens when a liquid material enters one end of a piping system and exits the other.

Learn more about pipe sizing chart and pipe scheduling (video)

Pipe Sizes and Pipe Schedule – A Complete Guide For Piping Professional by HardHat Engineer


Knowing the schedule of your pipes is crucial because a pipe’s thickness significantly affects the longevity of your piping system. Your plumbing system could sustain extra damage if your pipes crack, burst, leak, or carry a larger load than they are designed to handle. The proper stainless steel pipe supports may be more easily matched with your pipes to withstand an internal pressure bar. Mismatches can cause damage, on-site disasters, and project closure if your pipes are not matched to the appropriate ft pipe support at the proper size.

If you have enjoyed reading this article, on the pipe size, and nominal pipe size, please don’t forget to share your experience in the comments section!

Picture in this post is by Samuel Sianipar on Unsplash

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