The nominal diameter of Metric (e.g. M8) and Unified (e.g.  in) threads is the theoretical major diameter of the male thread, which is truncated (diametrically) by of the pitch from the dimension over the tips of the "fundamental" (sharp cornered) triangles. The resulting flats on the crests of the male thread are theoretically one eighth of the pitch wide (expressed with the notation "p" or 0.125"p"), although the actual geometry definition has more variables than that. A full (100%) UTS or ISO thread has a height of around 0.65"p".