A mole is the Avogadro's number of atoms or molecules. Avogadro constant is named after Italian scientist Amedeo Avogadro. It is the scaling factor between macroscopic and microscopic particles. It defines the basic relationship between physical constants and properties. Value of Avagadro's constant is 6.0221(30)+1023mol-1. Use the online Avogadro's Number Calculator to find the Avogadro number by providing the Number of atoms, Average atomic mass, density and volume.