# 7/8 — Plumbing fitting and pipe thread standards

For 7/8, thread standard is BSP; threads per inch (tpi) is 14; thread pitch (mm) is 1.814; major (outside) diameter (mm) is 30.201; minor diameter (mm) is 27.877, recorded from its source on 2026-08-12.

- **Thread standard:** BSP _(our reading, not quoted from the source)_
- **Nominal size:** 7/8
- **Threads per inch (TPI):** 14
- **Thread pitch (mm):** 1.814
- **Major (outside) diameter (mm):** 30.201 _(verified: appears in the quote below)_
- **Minor diameter (mm):** 27.877
- **Thread angle (degrees):** 55 _(our reading, not quoted from the source)_
- **Governing standard:** ISO 228-1 _(our reading, not quoted from the source)_

## What the source says

> 1.1890 | 30.201

## Source

- https://en.wikipedia.org/wiki/British_Standard_Pipe

Last verified: 2026-08-12. Review by: 2028-08-11.
Part of [Plumbing fitting and pipe thread standards](https://referencesource.org/plumbing-fitting-thread-standards/).