Average Atomic Mass Calculator
Result
Average Atomic Mass Calculator The Average Atomic Mass Calculator finds the weighted average mass of an element from the masses and natural abundances of its isotopes. Enter each isotope's mass (in atomic mass units) and its percent abundance, and you get — free online calculator.
Formula
- Average Atomic Mass Calculator calculates its result from Sum, Isotope Mass, Fractional Abundance. It uses the formula Average atomic mass = Σ(isotope mass × fractional abundance). Change any input to recalculate the result instantly.
- The main inputs are Sum, Isotope Mass, Fractional Abundance. Enter them in the units and format shown in the calculator.
- Use the units, labels and assumptions shown beside each input so the formula is applied consistently.
- Changing any input above recalculates the result with the same calculation engine used by this page.
Example: Average Atomic Mass
- Sum: 2
- Isotope Mass: 3
- Fractional Abundance: 4
Using Sum = 2, Isotope Mass = 3, Fractional Abundance = 4, the calculated result is 24.
Sample result: Calculating…
Frequently asked questions
What does the Average Atomic Mass calculate?
Average Atomic Mass Calculator The Average Atomic Mass Calculator finds the weighted average mass of an element from the masses and natural abundances of its isotopes. Enter each isotope's mass (in atomic mass units) and its percent abundance, and you get — free online calculator.
Which values should I enter?
Enter Sum, Isotope Mass, Fractional Abundance using the units and format shown beside each field.
What formula does this calculator use?
The calculator uses the following relationship: Average atomic mass = Σ(isotope mass × fractional abundance).
Why might my result differ from another source?
Results can differ when another source uses different units, rounding rules, conventions or assumptions. Compare the inputs and definitions before comparing results.
Does the result update automatically?
Yes. Changing an input updates the result using the same calculation engine shown on this page.