Pipe Size Conversion Chart: DN, Inch and OD
Pipe size conversion chart from DN10 to DN300: inch size and outside diameters of steel, threaded, PE, PP-R, copper and stainless press pipe side by side, mm.
For quick comparison only. Matched outside diameters do not guarantee the same bore, pressure class or fitting compatibility. When you change material, check the inside diameter and the system's own table.
Dimension drawing and symbols
- D
- Steel tube outside diameter, EN 10220 mm
DN and inch are nominal sizes. D in each column is the actual outside diameter of the pipe commonly matched in that material. The same DN means a different outside diameter in another material.
Columns
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Visible rows: 15
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| Steel, mm | Plastic, copper, stainless, mm | ||||||
|---|---|---|---|---|---|---|---|
| DN | inch | DEN 10220 | DASME | DEN 10255 | DPE, PP-R | Dcopper | Dstainless press |
| DN10 | 3/8 | 17.2 | 17.1 | no value | no value | 12.0 | no value |
| DN15 | 1/2 | 21.3 | 21.3 | 21.3 | 20.0 | 18.0 | 18.0 |
| DN20 | 3/4 | 26.9 | 26.7 | 26.9 | 25.0 | 22.0 | 22.0 |
| DN25 | 1 | 33.7 | 33.4 | 33.7 | 32.0 | 28.0 | 28.0 |
| DN32 | 1 1/4 | 42.4 | 42.2 | 42.4 | 40.0 | 35.0 | 35.0 |
| DN40 | 1 1/2 | 48.3 | 48.3 | 48.3 | 50.0 | 42.0 | 42.0 |
| DN50 | 2 | 60.3 | 60.3 | 60.3 | 63.0 | 54.0 | 54.0 |
| DN65 | 2 1/2 | 76.1 | 73.0 | 76.1 | 75.0 | 76.1 | 76.1 |
| DN80 | 3 | 88.9 | 88.9 | 88.9 | 90.0 | 88.9 | 88.9 |
| DN100 | 4 | 114.3 | 114.3 | 114.3 | 110.0 | 108.0 | 108.0 |
| DN125 | 5 | 139.7 | 141.3 | 139.7 | 140.0 | no value | no value |
| DN150 | 6 | 168.3 | 168.3 | 165.1 | 160.0 | no value | no value |
| DN200 | 8 | 219.1 | 219.1 | no value | no value | no value | no value |
| DN250 | 10 | 273.0 | 273.0 | no value | no value | no value | no value |
| DN300 | 12 | 323.9 | 323.8 | no value | no value | no value | no value |
Quick answers
- DN15 is 1/2 inch: steel pipe 21.3 mm, PE and PP-R 20 mm, copper 18 mm outside diameter. View in table
- DN20 is 3/4 inch: steel pipe 26.9 mm, PE and PP-R 25 mm, copper 22 mm outside diameter. View in table
- DN25 is 1 inch: steel pipe 33.7 mm, PE and PP-R 32 mm, copper 28 mm outside diameter. View in table
- DN32 is 1 1/4 inch: steel pipe 42.4 mm, PE and PP-R 40 mm, copper 35 mm outside diameter. View in table
- DN40 is 1 1/2 inch: steel pipe 48.3 mm, PE and PP-R 50 mm, copper 42 mm outside diameter. View in table
- DN50 is 2 inch: steel pipe 60.3 mm, PE and PP-R 63 mm, copper 54 mm outside diameter. View in table
- DN80 is 3 inch: steel pipe 88.9 mm, PE and PP-R 90 mm, copper 88.9 mm outside diameter. View in table
- DN100 is 4 inch: steel pipe 114.3 mm, PE and PP-R 110 mm, copper 108 mm outside diameter. View in table
Conditions and notes
Steel columns are outside diameters from EN 10220:2002, ASME B36.10M:2018 and EN 10255 medium series. Plastic, copper and press pipe columns are the common DN match in manufacturer charts, not a standard definition.
- For PE and PP-R pipe the nominal size is the outside diameter (DN/OD). A match such as 20 mm for DN15 is trade practice. One source gives 125 mm PP-R for DN100, this table shows the 110 mm given by most sources. For DN200 and DN250 the sources disagree, so the cell is blank.
- In copper and stainless press systems DN15 usually corresponds to an 18 mm tube. A 15 mm copper tube counts as DN12 in these sources. Some charts also show 57 mm copper for DN50 and 114 mm for DN100.
- Stainless pipe is also made to the outside diameters in the steel columns: EN ISO 1127 in the metric series and ASME B36.19M in the inch series. The press pipe column covers thin wall building services tubes.
- For DN150 EN 10220 gives 168.3 mm, EN 10255 medium series 165.1 mm, and for DN65 ASME gives 73.0 mm. Threaded and welded pipe can differ at the same DN.
- A blank cell means no common match for that DN was confirmed by two separate sources.
- CSV download is unavailable because the sources do not establish permission for reuse.
Shows at a glance which outside diameter corresponds to a DN when you change pipe material. Open the detailed table for wall thickness, weight and pressure class.
Sources
This table is for preliminary reference. Check the applicable standard and product conditions before use.
- Source 1. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 2. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 3. Product overview 2013, referencing EN 10220. Accessed: 2026-10-16
- Source 4. Undated catalogue referencing ASME B36.10. Accessed: 2026-10-16
- Source 5. Undated web table referencing ASME B36.10M. Accessed: 2026-10-16
- Source 6. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 7. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 8. Version accessed. Accessed: 2026-10-16
- Source 9. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 10. Version accessed. Accessed: 2026-10-16
- Source 11. Undated numerical table. The referenced edition is stated in the conditions.. Accessed: 2026-10-16
- Source 12. Version accessed. Accessed: 2026-10-16
- Source 13. Version accessed. Accessed: 2026-10-16
- Source 14. Version accessed. Accessed: 2026-10-16
Data version: 2026-10-16
Related calculators
Other tables
- DN to NPS Pipe Size Chart
- EN 10220 Steel Tube Sizes and Weight Chart
- Pipe Schedule Chart (NPS 1/8 to 24)
- Stainless Steel Pipe Schedule Chart (NPS 1/8 to 12)
- PE Pipe SDR Chart: Wall Thickness and PN (20 to 630 mm)
- PP-R Pipe Dimensions Chart (SDR 5 to 11)
- Copper Tube Size Chart (EN 1057)
- EN 10255 Medium Series Tube Chart
- EN 1092-1 Flange Dimensions Chart (PN 10 and PN 16)