This article deals with ways in which calculations and checks of basic parameters of beer can be performed based on the knowledge of two parameters. The importance of this method is growing with the increase in craft beer production in our country, i.e. mini breweries, home-brewing, etc. The calculations are based on Balling's equations, alcohol factors and attenuation quotients which have been published unchanged at least since 1876. In Balling's time, they were used to determine an extract with a specific gravity of 17.5 degrees C/17.5 degrees C. In current brewing, specific gravities of 20 degrees C/20 degrees C are used. For this reason, new alcohol factors of apparent attenuation were derived and based on linear regression. Regression coefficients of the dependence of the alcohol factor of apparent attenuation on the extract in original wort were calculated. Some variants of calculations based on two input parameters were incorporated into the beer composition calculator using formulas that replace extract and alcohol tables. The accuracy of the results from the calculator was checked with analyses from the Anton Paar automatic analyser and with analyses obtained by the distillation method. The calculator is available at www.balling.cz.