[en] Probabilistic calibration of radiocarbon dates consists of transformation of initial probability distribution of conventional radiocarbon date into calendric time scale according to specific shape of the calibration curve. Algorithm of the program CALIBRATION, developed by the authors, is based on the Bayes theorem. The program is written in Microsoft BASIC for IBM PC compatible microcomputer with Hercules graphic card. The program enables calibration of single dates and can be also applied to calibration of sets of arbitrary or related dates. The results are presented on screen of monitor in form of graphs including plots of probability density function and cumulative probability, and numerical data, including selected fundamental characteristics of the probability distribution of calendric age. 11 figs., 1 tab., 26 refs. (author)