AN Fitting Size Guide
You can always identify AN fittings based on the male thread size (outside diameter). These sizes are constant regardless of brand, hose type, or fitting configuration. If your fitting has a convex 37 degree flare at the end, the threads will tell you the AN size (and vice-versa).
| Male Thread Size | AN Size* | Equivalent Tube Size (Nominal OD) |
Hose ID** | Male fitting ID |
|---|---|---|---|---|
| 3/8-24 | 3AN | 3/16" | 0.13" | 0.12" |
| 7/16-20 | 4AN | 1/4" | 0.22" | 0.17" |
| 9/16-18 | 6AN | 3/8" | 0.34" | 0.30" |
| 3/4-16 | 8AN | 1/2" | 0.44" | 0.39" |
| 7/8-14 | 10AN | 5/8" | 0.56" | 0.48" |
| 1 1/16-12 | 12AN | 3/4" | 0.69" | 0.61" |
| 1 5/16-12 | 16AN | 1" | 0.88" | 0.84" |
* Note that these are the same as SAE O-Ring Port sizes, but O-Ring Port size numbers are normally called out as dash numbers (-4, -6, etc).
If you don't have a male fitting to measure, an accurate measurement of the female thread ID can point you to an AN size. Note that you must be absolutely sure that you have a female AN fitting or SAE O-ring boss port! Many of these internal diameter measurements are very close to those of other port types.
| Female Thread Minor ID | AN Size | Male Thread Size | Could Also Be! |
|---|---|---|---|
| 0.330" to 0.340" | 3AN | 3/8-24 | M10* (0.330" - 0.341") |
| 0.383" to 0.395" | 4AN | 7/16-20 | 1/8 NPT (0.36"), M12* (0.398") |
| 0.502" to 0.515" | 6AN | 9/16-18 | 1/4 NPT (0.47"), M14 (0.499") |
| 0.682" to 0.696" | 8AN | 3/4-16 | M20* (0.681" - 0.699") |
| 0.798" to 0.814" | 10AN | 7/8-14 | 1/2 NPT (0.75"), M22 (0.802" - 0.814") |
| 0.972" to 0.990" | 12AN | 1 1/16-12 | 3/4 NPT (0.95"), 1 1/8-7 UNC (0.970" - 0.998"), M27x2* (0.978" - 0.993") |
| 1.222" to 1.240" | 16AN | 1 5/16-12 | 1" NPT (1.20"), M33x2* (1.214" - 1.229") |
* The thread pitch on these metric sizes are also quite close to the thread pitch of some SAE sizes (1.0mm = 25.4 TPI, 1.25mm = 20.3 TPI, 1.5mm = 16.9 TPI, 2mm = 12.7 TPI). You must measure carefully to be sure!
