Vibrations Per Hour (vph)
A watch specification field known as Vibrations Per Hour (vph), used to describe or compare a measurable or identifying characteristic of a watch.
Also known as: VPH, Beats per hour, BPH, Beat rate, Alternations per hour
Definition
Vibrations per hour, abbreviated vph, counts the individual half-oscillations or 'beats' made by a mechanical watch balance in one hour. Because one complete oscillation contains two vibrations, a 4 Hz movement makes 8 vibrations per second and 28,800 vph. Other common rates include 21,600 vph (3 Hz) and 36,000 vph (5 Hz). The figure is often called beat rate in watch specifications.
Why it matters
Vph is useful for understanding movement architecture and the visible cadence of a mechanical seconds hand, but it should not be used alone as a ranking of quality or accuracy.