Biological Age Calculator

Biological Age: From Lifestyle to Blood Work

Two people can share a birthday and be a decade apart on the inside. This tool estimates that gap two ways — quickly from your habits, and more precisely from a nine-marker blood algorithm called PhenoAge.

Chronological age only counts your birthdays. Biological age tries to measure how fast your body is actually wearing — and the two can drift surprisingly far apart. The research gold standard for measuring it is an epigenetic clock, which reads chemical marks (DNA methylation) layered onto your genes over time.^[1] Those require a specialised lab. The calculator above uses two practical proxies: a lifestyle estimate, and PhenoAge, an algorithm you can run from an ordinary blood panel.

Where PhenoAge comes from

In 2018, Morgan Levine and colleagues published PhenoAge in the journal Aging.^[2] They started with 42 clinical markers measured in a large US population sample (NHANES III) and used statistical modelling to find the smallest set that best predicted the risk of dying. The winner was a combination of nine blood markers plus chronological age. The resulting "phenotypic age" outperformed chronological age at predicting all-cause mortality across nearly every subgroup studied.

The nine markers

PhenoAge reads nine routine markers, each a window onto a different aging system — metabolism, inflammation, kidney and liver function, immune status and red-cell health. Rather than rate them here, we keep the calculator neutral and explain each one in depth on a dedicated page: the PhenoAge blood markers, explained. It covers what every marker measures and what higher or lower values generally indicate, with references.

How to read your result

If your estimate is below your chronological age, your biology is running younger than your birthday. If it's above, the marker breakdown shows which values contribute most to the formula, so you know where to look. Because the model is built from routine labs, the levers are the familiar ones: metabolic health, inflammation, and the organ and blood markers that respond to sleep, exercise, body composition, alcohol and not smoking. The lifestyle changes with the best evidence for a longer, healthier life — building cardio fitness, keeping muscle, sleeping 7-8 hours, a Mediterranean-style diet, low alcohol and not smoking — are the same ones that tend to nudge these markers in the right direction over months.^[5]

An important caveat about single blood draws

PhenoAge is powerful over populations, but any one blood test is a snapshot. A cold, a hard workout the day before, dehydration, a flare of an inflammatory condition or certain medications can move CRP, white cells or glucose enough to shift the result by years — temporarily. The number is most meaningful when your markers are measured while you're well and fasted, and most useful watched as a trend over repeated tests rather than a one-off verdict. Treat a surprising result as a prompt to recheck and to talk to your doctor, not as a diagnosis.

PhenoAge vs. the epigenetic gold standard

If you want the most direct measure of biological age, laboratory epigenetic clocks — Horvath's original clock, the newer DNAm PhenoAge, and pace-of-aging measures such as DunedinPACE — read your DNA methylation and are the research reference standard.^[1] They cost more and need a dedicated test. The blood-based PhenoAge you can calculate above is the practical, no-extra-cost proxy: it uses labs you may already have, it's validated against mortality, and you can repeat it every time you get blood drawn.