Description: In article the procedure of uncertainty evaluation of the result of measurement is considered at expression of input quantities in decibels. The ratio for recalculation of an arithmetic mean, standard uncertainties of type A and B, the combined standard and expanded uncertainties for the quantities expressed in decibels into corresponding characteristics for output quantities were received. Values of the relative errors appeared in these cases were calculated. The conditions at which these errors can be neglected were defined.
Keywords: uncertainty of measurement, standard uncertainty, combined standard uncertainty, expanded uncertainty, decibel, a method of Monte-Carlo