The R package masscor provides functions, classes and methods to support mass measurements using digital balances. The provided classes can store the calibration information for balances and mass standards, to later allow the conversion of balance readings to both conventional mass and real mass, and to perform routine balance verification by using the normalized error function. Air buoyancy correction factors are calculated using local air density that can be calculated using measured environmental conditions and applying one of several models available in the package. The uncertainty of (corrected) mass measurements can also be calculated allowing to further asses the suitability of a given mass measurement.