How biological age is measured

Biological age is an estimate of physiological age derived from measurable biomarkers or models — not calendar years. Different methods measure it from different inputs: blood chemistry, DNA methylation, imaging, or other biological signals.

Blood-based

• PhenoAge (Levine Phenotypic Age)
• Klemera-Doubal Biological Age (KDM)
• GlycanAge

Epigenetic (DNA methylation)

• GrimAge
• DunedinPACE

Imaging

• Retinal age (deep-learning retinal aging clock)

Try the PhenoAge calculator — clinical PhenoAge (2018), computed from nine routine blood markers and age with its published coefficients.

See the full method catalog →