A method for calibrating the big liquid-argon spectrometer (BARS), which is
part of the Tagged Neutrino Facility of the U-70 accelerator system, is de
scribed. The method is based on the detection of muons stopped in the spect
rometer. The iteration procedure is proposed for finding the calibration co
efficients by comparing the experimental data with the results of simulatio
n, obtained in view of the measured noises and readout thresholds of the da
ta-acquisition system. This calibration method also can be used for other h
ighly granulated calorimeters with a low detection threshold.