Copper Pipe Sizes: Complete Size Chart in mm & Inches (Types K, L & M)

Ordering copper pipe by the wrong number costs time and money. A 1/2-inch nominal ASTM B88 water tube has a 5/8-inch outside diameter (OD), while 1/2-inch ACR tube is sized by its actual outside diameter. Copper pipe sizing follows different conventions depending on the standard: ASTM B88 water tube uses nominal sizes, ASTM B280 ACR tube uses actual OD, and metric water tubes such as EN 1057 are identified by their actual outside diameter in millimetres. This guide from El Buroj gives you one clear chart with OD, ID, and wall thickness for Types K, L, M, and ACR, plus the pipe sizes Saudi projects use for split AC units.

What Are the Standard Copper Pipe Sizes?

Standard copper pipe sizes under ASTM B88 range from 1/4 inch to 12 inches in nominal diameter, while EN 1057 covers metric copper tubes identified by their actual outside diameter (OD), starting at 6 mm.

For ASTM B88 water tube, the actual OD is 1/8 inch larger than the nominal size. The following dimensions cover common ASTM B88 sizes in Types K, L and M. Wall thickness and inside diameter (ID) are shown in millimetres for easier comparison. ID is calculated by subtracting twice the wall thickness from the actual OD.

1/4 inch nominal: OD 9.53 mm. Type K wall 0.89 mm, ID 7.75 mm. Type L wall 0.76 mm, ID 8.01 mm. Type M is not available in this size.
3/8 inch nominal: OD 12.70 mm. Type K wall 1.24 mm, ID 10.22 mm. Type L wall 0.89 mm, ID 10.92 mm. Type M wall 0.64 mm, ID 11.42 mm.
1/2 inch nominal: OD 15.88 mm. Type K wall 1.24 mm, ID 13.40 mm. Type L wall 1.02 mm, ID 13.84 mm. Type M wall 0.71 mm, ID 14.46 mm.
5/8 inch nominal: OD 19.05 mm. Type K wall 1.24 mm, ID 16.57 mm. Type L wall 1.07 mm, ID 16.91 mm. Type M is not available in this size.
3/4 inch nominal: OD 22.23 mm. Type K wall 1.65 mm, ID 18.93 mm. Type L wall 1.14 mm, ID 19.95 mm. Type M wall 0.81 mm, ID 20.61 mm.
1 inch nominal: OD 28.58 mm. Type K wall 1.65 mm, ID 25.28 mm. Type L wall 1.27 mm, ID 26.04 mm. Type M wall 0.89 mm, ID 26.80 mm.
1-1/4 inches nominal: OD 34.93 mm. Type K wall 1.65 mm, ID 31.63 mm. Type L wall 1.40 mm, ID 32.13 mm. Type M wall 1.07 mm, ID 32.79 mm.
1-1/2 inches nominal: OD 41.28 mm. Type K wall 1.83 mm, ID 37.62 mm. Type L wall 1.52 mm, ID 38.24 mm. Type M wall 1.24 mm, ID 38.80 mm.
2 inches nominal: OD 53.98 mm. Type K wall 2.11 mm, ID 49.76 mm. Type L wall 1.78 mm, ID 50.42 mm. Type M wall 1.47 mm, ID 51.04 mm.
2-1/2 inches nominal: OD 66.68 mm. Type K wall 2.41 mm, ID 61.86 mm. Type L wall 2.03 mm, ID 62.62 mm. Type M wall 1.65 mm, ID 63.38 mm.
3 inches nominal: OD 79.38 mm. Type K wall 2.77 mm, ID 73.84 mm. Type L wall 2.29 mm, ID 74.80 mm. Type M wall 1.83 mm, ID 75.72 mm.

These dimensions apply to the listed ASTM B88 sizes only. Confirm the tube marking, specified type and manufacturer's dimensional data before ordering or selecting compatible fittings.

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Copper Pipe Size Chart in mm and Inches (OD, ID & Wall Thickness)

The main chart covers ASTM B88 water tube. Each standard below uses its own sizing logic, so match the table to your job.

Copper Pipe Sizes in Inches (ASTM B88 - Nominal vs Actual OD)

ASTM B88 names pipe by nominal size, which is a label and not a measurement. Add 1/8 inch to get the real OD.

1/2 inch nominal measures 0.625 inch OD (15.88 mm)
3/4 inch nominal measures 0.875 inch OD (22.23 mm)
1 inch nominal measures 1.125 inch OD (28.58 mm)

Fittings are sold by the same nominal size as the pipe they join.

Copper Pipe Sizes in mm (EN 1057 Metric Sizes)

EN 1057 copper pipe sizes are measured by their actual outside diameter (OD), meaning a 22 mm pipe has an OD of exactly 22 mm. Available wall thicknesses vary depending on the pipe temper and intended application.

Common metric copper pipe sizes include:

- 6–10 mm: 0.6–0.8 mm wall thickness, small feeds.
- 12 mm: 0.6–1.0 mm, fixture connections.
- 15–18 mm: 0.7–1.0 mm, water branches.
- 22–28 mm: 0.9–1.2 mm, larger branches and risers.
- 35–42 mm: 1.2–1.5 mm, risers and mains.
- 54 mm: 1.5–2.0 mm, main distribution.
- 76.1–108 mm: 2.0–2.5 mm, large distribution systems.

AC & Refrigeration Copper Pipe Sizes (ASTM B280: 1/4" to 1-5/8")

AC and refrigeration copper pipe sizes under ASTM B280 are measured by their actual outside diameter (OD), with no nominal size adjustment. Soft copper coils are annealed for flexibility, while hard straight lengths are drawn for rigid installations.

Common ACR copper tube sizes include:

1/4 inch: 6.35 mm OD, 0.030-inch soft coil.
3/8 inch: 9.53 mm OD, 0.032-inch soft, 0.030-inch hard.
1/2 inch: 12.70 mm OD, 0.032-inch soft, 0.035-inch hard.
5/8 inch: 15.88 mm OD, 0.035-inch soft, 0.040-inch hard.
3/4 inch: 19.05 mm OD, 0.035-inch soft, 0.042-inch hard.
7/8 inch: 22.23 mm OD, variable soft, 0.045-inch hard.
1-1/8 inch: 28.58 mm OD, variable soft, 0.050-inch hard.
1-3/8 inch: 34.93 mm OD, variable soft, 0.055-inch hard.
1-5/8 inch: 41.28 mm OD, variable soft, 0.060-inch hard.

El Buroj stocks the ASCO 3/4 inch copper tube roll, along with Mueller 5/8 inch and Mueller 7/8 inch rolls.

Understanding Copper Pipe Diameters: Nominal, Outside (OD) & Inside (ID)

Three different numbers describe one pipe, and each answers a different question.

Nominal: the name on the label. It tells you the product family, not the dimension.
Outside diameter (OD): the measured width of the tube. Fittings, clips and insulation match this number.
Inside diameter (ID): OD minus two walls. It controls flow and pressure drop.

A Type K pipe has a smaller ID than a Type L pipe of the same nominal size, because its wall is thicker.

Types of Copper Pipe: K, L, M & ACR

Type K Copper Tube

Type K has the thickest wall among ASTM B88 Types K, L and M, generally providing a higher tube pressure rating at the same nominal size and temper. Its suitability for underground service lines, mains or fire protection depends on the approved project specification, applicable code, operating pressure, temperature and joining method. Type K is commonly identified by a green marking.

Type L Copper Tube

Type L has an intermediate wall thickness between Types K and M. It is used in a range of plumbing and water distribution applications, subject to project requirements and applicable standards. Type L is commonly identified by a blue marking.

Type M Copper Tube

Type M has the thinnest wall among the three ASTM B88 types and may be specified for certain applications where its dimensions and pressure capacity meet the design requirements. Do not select it solely on cost or a general description such as “light interior work.” Type M is commonly identified by a red marking.

Selection note: Type selection must follow the approved project specification and applicable code. Fire protection applications require confirmation by the responsible engineer before specifying or accepting the tube.

ACR Copper Tube (Soft Coils vs Hard Straight Lengths)

ACR tube is cleaned and sealed for refrigerant circuits. Soft coils bend around obstacles on split AC runs, while hard straight lengths suit rigid pipework and larger sizes.

Browse our copper conduits for ready AC rolls.

Copper Pipe Wall Thickness & Pressure Ratings

Copper tube pressure ratings depend on nominal size, wall thickness, material temper, operating temperature and the applicable design conditions. The following values are tube pressure ratings for 1/2-inch nominal ASTM B88 copper tube at the stated temperature condition of up to 66°C. They are not pressure ratings for a complete piping system.

Type K: 758 psi annealed, 52.3 bar annealed, 1,490 psi drawn, 102.7 bar drawn.
Type L: 613 psi annealed, 42.3 bar annealed, 1,206 psi drawn, 83.2 bar drawn.
Type M: 420 psi annealed, 29.0 bar annealed, 825 psi drawn, 56.9 bar drawn.

Source: Copper Development Association, Copper Tube Handbook, Table 14.3. Values should be checked against the applicable handbook edition and reviewed by the project engineer before specification or use.

Tube ratings alone do not establish the allowable pressure of the complete system. Fittings, joints, joining procedures, operating temperature and other system components may determine the governing pressure limit. The applicable rating must be verified for the complete assembly.

Copper Pipe Weight Chart per Meter

The following are the theoretical copper pipe weights per meter, calculated using ASTM B88 wall thicknesses. These values help estimate the total material weight, transportation load, and project costs.

Copper pipe weights per meter (kg/m) vary by size and type:

1/4 inch: K 0.22, L 0.19.
3/8 inch: K 0.40, L 0.29, M 0.22.
1/2 inch: K 0.51, L 0.42, M 0.30.
5/8 inch: K 0.62, L 0.54.
3/4 inch: K 0.95, L 0.68, M 0.49.
1 inch: K 1.25, L 0.97, M 0.69.
1-1/4 inch: K 1.54, L 1.32, M 1.01.
1-1/2 inch: K 2.03, L 1.70, M 1.40.
2 inches: K 3.07, L 2.61, M 2.17.
2-1/2 inches: K 4.36, L 3.69, M 3.02.
3 inches: K 5.96, L 4.95, M 3.98.

Buying by the hundreds of meters? Request bulk quotation and we will price it by size and type.

Most Common Copper Pipe Sizes and Their Uses

Copper Pipe Sizes for Plumbing & Water Supply

Copper tube sizing for plumbing depends on the specified standard, actual tube dimensions and hydraulic design. The following are illustrative applications, not universal sizing recommendations for Saudi buildings.

ASTM B88 nominal sizes

1/2-inch nominal: commonly used for individual fixture branches, subject to flow demand and design requirements.
3/4-inch nominal: may be used for larger branches where calculated flow and pressure requirements justify it.
1-inch nominal: may be specified for distribution sections or risers according to the hydraulic design.

EN 1057 metric sizes Metric copper tubes are identified by actual outside diameter. For example, 15 mm, 22 mm and 28 mm OD tubes are metric dimensions and must not be treated as identical to ASTM B88 nominal sizes.

Always select tube dimensions using the hydraulic calculations, approved project specification and compatible fittings.

For other plumbing materials, see our plumbing pipes.

Copper Pipe Sizes for Split AC (by Ton Capacity)

A split AC system typically uses a liquid line and a suction line, but their required diameters are determined by the exact equipment model and installation conditions.

Select line sizes from the exact unit’s installation manual; capacity alone is insufficient.

For a useful comparison, list copper line sizes only alongside the manufacturer, exact model number, refrigerant type and the relevant installation-manual reference. Pipe diameter, maximum line length, elevation differences and any permitted adjustments must follow the manufacturer's instructions.

Do not increase suction-line diameter automatically because a run is longer. Follow the manufacturer's stated limits and sizing requirements.

Always confirm the required tube dimensions before ordering.

Insulate both lines with our air conditioning insulation, and see the full range of air conditioning accessories.

How to Measure Copper Pipe Size Correctly

Measure the outside, then read the chart. Wrap a strip of paper around the pipe, mark the overlap, and divide the length by 3.1416 to get the OD.

A caliper is faster and more accurate for measuring the outside diameter. Measuring wall thickness at the cut end can help compare the tube against published dimensional tables, but it does not establish the tube type or confirm compliance on its own. Check the tube marking and the manufacturer's certificate or data sheet to verify the standard, type and dimensions.

Apply the correct sizing convention:

For ASTM B88 water tube, subtract 1/8 inch from the actual OD in inches to identify the nominal size.
For ASTM B280 ACR tube, the size refers to the actual outside diameter.
For metric tubes such as EN 1057, use the specified actual OD in millimetres.

Do not identify a tube solely by measurement when conformity or fitting compatibility matters.

Copper Pipe Size Conversion: mm to Inches

To convert an actual outside diameter (OD) from millimetres to inches, divide it by 25.4. This is a mathematical conversion, not an ASTM nominal size conversion.

For reference, 15 mm equals 0.591 inches, 22 mm equals 0.866 inches, 28 mm equals 1.102 inches, 35 mm equals 1.378 inches, and 54 mm equals 2.126 inches.

Nearby metric and ASTM sizes are not interchangeable. For example, 1/2-inch nominal ASTM B88 tube has an OD of 15.88 mm, while 3/4-inch, 1-inch, 1-1/4-inch and 2-inch nominal tubes have ODs of 22.23 mm, 28.58 mm, 34.93 mm and 53.98 mm, respectively. Confirm tube and fitting compatibility before ordering.

Copper Pipe Standards Used in Saudi Arabia (ASTM B88, B280, EN 1057, JIS H3300)

Four standards cover nearly every copper tube supplied in the Kingdom.

ASTM B88: water tube in Types K, L and M, sized by nominal size
ASTM B280: ACR tube for air conditioning and refrigeration, sized by actual OD
EN 1057: metric tube for water, gas and heating, sized by actual OD in mm
JIS H3300: Japanese standard for seamless copper tube, a common reference for Asian-made AC copper

Ask for the standard marking before you accept any delivery, and check dimensions against the tables above.

Request Copper Tube Supply for Your Project from El Buroj

El Buroj supplies copper tube products for AC and refrigeration projects. Check the available products and specifications in our copper tube listings, or contact our sales team to request a quotation for your required dimensions and quantities. Confirm current brands, sizes and availability before ordering.

Send your BOQ or tube specifications, quantities and delivery requirements to request a project quotation. Include the application, applicable standard, nominal size or actual OD, wall thickness, temper, product format (coils or straight lengths), quantity and unit, delivery city and required delivery date.

Prefer to talk? Call 920031298.

Choosing the Right Copper Pipe Sizes

Getting copper pipe sizes right comes down to three checks: which standard the pipe follows, whether the size is nominal or actual OD, and which wall thickness the job needs. Use the main chart for plumbing and the ACR chart for split AC lines.

For stock in the sizes you need, message El Buroj on WhatsApp to request a project quotation, or call us : 920031298.

FAQs

What are the standard sizes of copper pipes?

Standard copper pipe sizes run from 1/4 to 12 inch nominal under ASTM B88 and from 6 mm upward under EN 1057. For AC work, ACR tube runs from 1/4 to 1-5/8 inch OD.

What are the most common copper pipe sizes?

The most common sizes are 1/2, 3/4 and 1 inch for plumbing, and 1/4, 3/8, 1/2 and 5/8 inch for split AC lines. In metric, 15, 22 and 28 mm dominate.

What size is 32 mm pipe?

A 32 mm outside diameter equals approximately 1.26 inches mathematically. This conversion does not identify an ASTM nominal size or establish a compatible replacement. Availability depends on the applicable standard and manufacturer's catalogue. Confirm the actual OD, tube specification and fitting compatibility before selecting a replacement.

What are the four types of copper pipe?

Types K, L and M are ASTM B88 water tube classifications with different wall thicknesses. Type K has the thickest wall, Type L has an intermediate wall, and Type M has the thinnest wall. ACR copper tube is covered by ASTM B280 for air conditioning and refrigeration applications and is sized by its actual outside diameter (OD).

What size copper pipe is used for a 1.5 ton split AC?

The required liquid-line and suction-line diameters depend on the exact AC model and its installation requirements. Check the outdoor unit's installation manual for the specified tube sizes, refrigerant and permitted piping lengths before purchasing.

What is the price of a 12 mm copper pipe?

Copper tube prices depend on wall thickness, temper, length, product format and brand, so no single price applies. For a quotation, specify 12 mm OD, wall thickness, temper, length and quantity. Contact El Buroj to check availability and request current pricing.