Beyond the Codices, eds. Arthur J.O. Anderson, Frances Berdan, and James Lockhart (Los Angeles: UCLA Latin American Center, 1976), 26.
most commonly measured from the human foot up to the top of the hand with the arm raised above the head (see Castillo quote in the Spanish attestations field); citing Ixtlilxochitl, Castillo concludes that this is about 2.5 meters (which is three varas of 0.8359 meters per vara); citing Birgitta Leander, it may be 2 meters (giving an average height of 1.6 meters to the indigenous male)
Víctor M. Castillo F., "Unidades nahuas de medida," Estudios de Cultura Náhuatl 10 (1972), 195–223, see page 213.