Search Ctrl K
Home / Tools
THE FEUTEX TOOLKIT

Two-Isotope Mean Atomic Mass

Calculate abundance-weighted atomic mass and isotope contribution for a two-isotope model.

Chemistry workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaMean atomic mass = a*fraction/100+b*(1-fraction/100); Second isotope abundance = 100-fraction
Sources and model references

Worked example

Inputs

First isotope mass
10 u
Second isotope mass
11 u
First isotope abundance
20 %

Expected results

Mean atomic mass
10.8 u
Second isotope abundance
80 %

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Calculate abundance-weighted atomic mass and isotope contribution for a two-isotope model.
  2. Set first isotope mass, second isotope mass, first isotope abundance in the indicated units.
  3. Calculate and compare mean atomic mass, second isotope abundance.

Try this example

{
  "a": 10,
  "b": 11,
  "fraction": 20
}

Accuracy and scope

Idealized educational model. Enter measured values in the displayed units; real systems may require additional corrections.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.