Engineering reference · ASME B16.5
ASME B16.5 Flange Dimension Finder
Pick a flange type, pressure class and pipe size. The 3D model is drawn to scale for the size you pick and cut open so you can see the section. Each dimension on the model matches a line in the result list.
Find a flange size by type, class and NPS
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O, outside diameter: 152.4 mm
Drag to turn it any way, or use Front, Side and 3/4; on a phone, swipe sideways to turn. Scroll to zoom. Drawn to scale for the selected size. The bar shows a round length.
| NPSDN | OOutside diameter | tfFlange thickness, min. | RRaised face diameter | WBolt circle diameter | n×⌀Bolt holes | BoltsBolt size | XHub diameter at base | AHub diameter at weld end | YLength through hub | BBore |
|---|---|---|---|---|---|---|---|---|---|---|
| ½DN 15 | 88.9 | 9.7 | 35.1 | 60.5 | 4 × ⌀15.7 | 4 × 1/2" | 30.2 | 21.3 | 46.2 | 15.8 |
| ¾DN 20 | 98.6 | 11.2 | 42.9 | 69.8 | 4 × ⌀15.7 | 4 × 1/2" | 38.1 | 26.7 | 50.8 | 20.9 |
| 1DN 25 | 107.9 | 12.7 | 50.8 | 79.2 | 4 × ⌀15.7 | 4 × 1/2" | 49.3 | 33.5 | 54.1 | 26.6 |
| 1¼DN 32 | 117.3 | 14.2 | 63.5 | 88.9 | 4 × ⌀15.7 | 4 × 1/2" | 58.7 | 42.2 | 55.6 | 35.1 |
| 1½DN 40 | 127.0 | 15.7 | 73.2 | 98.6 | 4 × ⌀15.7 | 4 × 1/2" | 65.0 | 48.3 | 60.5 | 40.9 |
| 2DN 50 | 152.4 | 17.5 | 91.9 | 120.6 | 4 × ⌀19.0 | 4 × 5/8" | 77.7 | 60.5 | 62.0 | 52.5 |
| 2½DN 65 | 177.8 | 20.8 | 104.6 | 139.7 | 4 × ⌀19.0 | 4 × 5/8" | 90.4 | 73.2 | 68.3 | 62.7 |
| 3DN 80 | 190.5 | 22.4 | 127.0 | 152.4 | 4 × ⌀19.0 | 4 × 5/8" | 107.9 | 88.9 | 68.3 | 77.9 |
| 3½DN 90 | 215.9 | 22.4 | 139.7 | 177.8 | 8 × ⌀19.0 | 8 × 5/8" | 122.2 | 101.6 | 69.8 | 90.1 |
| 4DN 100 | 228.6 | 22.4 | 157.2 | 190.5 | 8 × ⌀19.0 | 8 × 5/8" | 134.9 | 114.3 | 74.7 | 102.3 |
| 5DN 125 | 254.0 | 22.4 | 185.7 | 215.9 | 8 × ⌀22.4 | 8 × 3/4" | 163.6 | 141.2 | 87.4 | 128.2 |
| 6DN 150 | 279.4 | 23.9 | 215.9 | 241.3 | 8 × ⌀22.4 | 8 × 3/4" | 192.0 | 168.4 | 87.4 | 154.1 |
| 8DN 200 | 342.9 | 26.9 | 269.7 | 298.4 | 8 × ⌀22.4 | 8 × 3/4" | 246.1 | 219.2 | 100.1 | 202.7 |
| 10DN 250 | 406.4 | 28.7 | 323.8 | 361.9 | 12 × ⌀25.4 | 12 × 7/8" | 304.8 | 273.1 | 100.1 | 254.5 |
| 12DN 300 | 482.6 | 30.2 | 381.0 | 431.8 | 12 × ⌀25.4 | 12 × 7/8" | 365.3 | 323.8 | 112.8 | 304.8 |
| 14DN 350 | 533.4 | 33.5 | 412.8 | 476.3 | 12 × ⌀28.4 | 12 × 1" | 400.0 | 355.6 | 125.5 | 336.5 |
| 16DN 400 | 596.9 | 35.1 | 469.9 | 539.8 | 16 × ⌀28.4 | 16 × 1" | 457.2 | 406.4 | 125.5 | 387.3 |
| 18DN 450 | 635.0 | 38.1 | 533.4 | 577.9 | 16 × ⌀31.8 | 16 × 1-1/8" | 505.0 | 457.2 | 138.2 | 438.1 |
| 20DN 500 | 698.5 | 41.4 | 584.2 | 635.0 | 20 × ⌀31.8 | 20 × 1-1/8" | 558.8 | 508.0 | 143.0 | 488.9 |
| 24DN 600 | 812.8 | 46.2 | 692.1 | 749.3 | 20 × ⌀35.1 | 20 × 1-1/4" | 663.4 | 609.6 | 150.9 | 590.5 |
Select a row to show that size on the drawing.
ASME B16.5 Class 150 flange dimensions: OD, thickness and hub diameter
Outside diameter, minimum flange thickness and hub diameter for Class 150 flanges, NPS 1/2 to 24, from ASME B16.5-2020 Table 8 and 8C, in millimetres and inches. These are the values in our Class 150 check sheet; for other classes and dimensions, use the finder above.
| NPS | Flange OD (mm) | Flange OD (in) | Min. thickness (mm) | Min. thickness (in) | Hub dia. (mm) | Hub dia. (in) |
|---|---|---|---|---|---|---|
| 1/2 | 89 | 3.5 | 9.7 | 0.38 | 30 | 1.19 |
| 3/4 | 99 | 3.88 | 11.2 | 0.44 | 38 | 1.5 |
| 1 | 108 | 4.25 | 12.7 | 0.5 | 49 | 1.94 |
| 1 1/4 | 117 | 4.62 | 14.2 | 0.56 | 59 | 2.31 |
| 1 1/2 | 127 | 5 | 15.9 | 0.62 | 65 | 2.56 |
| 2 | 152 | 6 | 17.5 | 0.69 | 78 | 3.06 |
| 2 1/2 | 178 | 7 | 20.6 | 0.81 | 90 | 3.56 |
| 3 | 190 | 7.5 | 22.4 | 0.88 | 108 | 4.25 |
| 3 1/2 | 216 | 8.5 | 22.4 | 0.88 | 122 | 4.81 |
| 4 | 229 | 9 | 22.4 | 0.88 | 135 | 5.31 |
| 5 | 254 | 10 | 22.4 | 0.88 | 164 | 6.44 |
| 6 | 279 | 11 | 23.9 | 0.94 | 192 | 7.56 |
| 8 | 343 | 13.5 | 26.9 | 1.06 | 246 | 9.69 |
| 10 | 406 | 16 | 28.4 | 1.12 | 305 | 12 |
| 12 | 483 | 19 | 30.2 | 1.19 | 365 | 14.38 |
| 14 | 533 | 21 | 33.3 | 1.31 | 400 | 15.75 |
| 16 | 597 | 23.5 | 35.1 | 1.38 | 457 | 18 |
| 18 | 635 | 25 | 38.1 | 1.5 | 505 | 19.88 |
| 20 | 698 | 27.5 | 41.1 | 1.62 | 559 | 22 |
| 22 | 749 | 29.5 | 44.4 | 1.75 | 610 | 24 |
| 24 | 813 | 32 | 46 | 1.81 | 663 | 26.12 |
Which table should we add next?
We add one standard at a time, each checked against at least two sources. Pick the one you look up most and it moves up our list.
How the numbers are stated. Values follow the current ASME B16.5 convention: flange thickness (tf) and hub lengths (Y) exclude the raised face. The raised face is 0.06 in (about 2 mm) high on Class 150 and 300 and 0.25 in (about 7 mm) on Class 600 and above. Lap-joint flanges have no raised face. Inch values are the master figures; millimetres are the inch values × 25.4.
Reference only. This page is a buying aid compiled and cross-checked by BLD Forge Direct. It is not the standard. Machining, tolerances and acceptance go by the purchased edition of ASME B16.5 and your project drawing. Weld-neck bores follow the pipe schedule you specify.
Data checked 2026-10-10 · sizes NPS ½ to 24 · Classes 150 to 2500.