Chronological (calendar) age is the number of years, months and days that have passed since birth. It is the simplest and most objective indicator, but it is the same for all peers and does not reflect individual differences in health.
In longevity medicine it is compared with biological age: the difference between them shows whether a person is aging faster or slower than average.
Why calendar age alone is not enough
With age the risk of most diseases statistically rises, so calendar age is a convenient reference point. But it does not account for individual differences: two 50-year-olds can be in very different shape.
That is why in preventive medicine chronological age is supplemented with an estimate of biological age.
The reference point for all "aging clocks"
Practically all methods of assessing aging are calibrated against chronological age: epigenetic clocks and blood indices (PhenoAge) are trained to predict the number of years lived or the risk of death.
The difference "biological minus chronological age" is called age acceleration: a positive value means the person is aging faster than average.
Calculate using this marker
Calculators where Chronological age is used directly:
Frequently asked questions
Can biological age be less than chronological age?
Yes. If the body is in good shape, biological age can be several years below calendar age — a favorable sign associated with a lower risk of disease.
Why do we need chronological age if we have biological age?
Chronological age is an objective and free reference point. Without it, age acceleration cannot be calculated: the biological "clocks" are always compared specifically with the number of years lived.
Related terms
Sources
- Wikipedia — Ageing
- Wikipedia — Epigenetic clock
- Levine et al. An epigenetic biomarker of aging (Aging, 2018)