KDM · Klemera–Doubal 2006
KDM Biological Age
The Klemera–Doubal Method estimates biological age by combining several biomarkers against reference-population trends. It runs in your browser — your numbers never leave this page.
Your biomarkers
From a recent lab panel & check-up
Units
Your KDM biological age
—years
Fill in your age and the eight biomarkers to see your estimated biological age. Values update as you type.
Educational estimate only — not medical advice. KDM depends on the reference population used; see the note below.
About the reference parameters. KDM requires each biomarker's trend across a reference population (slope, intercept, residual spread). This calculator ships with illustrative parameters so you can see the method in action; the production Verith app uses cohort-validated values. Treat the number here as a demonstration, not a clinical result.
The method
Klemera & Doubal (2006) regress each biomarker on age in a reference sample, then find the age that best fits your combined values — weighted by how tightly each marker tracks age.
PhenoAge vs KDM
PhenoAge is tuned to mortality risk; KDM is tuned to the aging trajectory of a population. They answer related but distinct questions. Try PhenoAge →
Want it tracked?
Verith for iPhone computes KDM biological age with every lab import and plots how it moves over time. See the app →