Atomic Mass Calculator
Calculate atomic mass of elements and isotopes using atomic number, mass number, and isotopic abundance.
Enter Element Data
Multiple Isotopes
Results
Enter element data to calculate atomic mass
Atomic Mass Concepts
Key Definitions
- • Atomic Number (Z): Number of protons
- • Mass Number (A): Protons + neutrons
- • Isotope: Same Z, different A
- • Atomic Mass: Mass of isotope in amu
- • Average Atomic Mass: Weighted average
Common Elements
- • Carbon (C): ~12.011 amu
- • Hydrogen (H): ~1.008 amu
- • Oxygen (O): ~15.999 amu
- • Nitrogen (N): ~14.007 amu
- • Iron (Fe): ~55.845 amu