This article proposes a volumctric-hydrochemical method for determining the duration of growth and age of karst cavities on the basis of a geometric progression of doubling the volume of the karst cavity. The period of doubling the volume of the karstic cavity is calculated from the added mineralization of water passing through the cavity in a certain time. The duration of formation and age of the karst cavity can coincide, as in the Ordinsky cave, and do not coincide, as in the Kungur ice cave.