FHZ

FHZ can refer to:


 * Femtohertz, an SI unit for frequency equivalent to one quintillionth of a hertz
 * Fakahina Airfield, an airfield in Fakahina atoll, French Polynesia, by IATA code
 * $$F_{HZ}$$, the fraction of stars with rocky planets in the habitable zone, in Seager's variant of the Drake equation; see Drake equation