Isotope Abundance Calculator
Enter isotope masses and fractional or percentage abundances to normalize and calculate a weighted average.
A QUICK WALKTHROUGH
How to use this tool
- Enter at least two complete isotope mass/abundance rows, using one mass unit.
- Choose fractional or percentage abundances.
- Review normalized proportions and weighted average mass.
Explicit input assumption
Your complete rows are the entire isotope set you intend to model. No isotope identification, reference-table verification or inference of omitted species is performed. Incomplete optional rows are ignored.
Normalization and weighted mean
Abundances are normalized by their positive total. Weighted mean = Σ(mass × normalized abundance). Percentage mode divides inputs by100 before normalization.
GOOD TO KNOW
Common questions
Must abundances sum to one?
No. Nonnegative values with a positive total are normalized.
Can I enter percentages?
Yes. Percentage mode converts and normalizes values such as98.9 and1.1.
Does it identify real isotopes?
No. It only uses masses and abundances you provide.