What this calculator does
Average atomic mass from isotopes works out weighted average atomic mass of an element from its isotope masses and natural abundances. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaM = Σ(massᵢ × abundanceᵢ)
The inputs explained
| Field | What to enter |
|---|---|
| Mass of each isotope, amu (comma-separated) | A list of numbers, separated by commas or spaces. |
| Natural abundance of each isotope, % (comma-separated) | A list of numbers, separated by commas or spaces. |