What if your biological age were not the one on your ID card? Recent geroscience research shows that two individuals of the same chronological age can differ by 10 to 15 years in biological age depending on their metabolic, inflammatory and immune status. Epigenetic clocks (Horvath, GrimAge, DunedinPACE) can estimate that gap, but at a cost of €150 to €500 with no reimbursement. A scientifically validated alternative exists: the PhenoAge by Levine et al. (2018), computed from 9 biomarkers found in any standard blood panel.
I have built a free and open-source calculator, hosted on GitHub and usable directly below — no sign-up, no data leaves your device. All computations run client-side in your browser.
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Where does PhenoAge come from?
PhenoAge was published in 2018 in Aging (Albany NY) by Morgan Levine (Yale School of Medicine) and her team, in collaboration with Steve Horvath, one of the founding fathers of epigenetic clocks. The team selected 9 clinical biomarkers out of 42 candidates on the American NHANES III cohort (n = 9,926), using a Gompertz regression to model 10-year all-cause mortality. The formula was then independently validated on NHANES IV, UK Biobank, Framingham and the Rotterdam Study.
Published findings: each standard deviation of phenotypic age acceleration (PhenoAge − chronological age) is associated with an all-cause mortality hazard ratio of 1.14 [95% CI 1.10–1.18], independent of chronological age. PhenoAge also predicts incident cancers, cardiovascular disease and dementia.
The 9 biomarkers to ask your GP for
All markers below are prescribable by any physician (GP or specialist) and routinely covered by national health systems in most European countries:
| Biomarker | SI unit | Reference range |
|---|---|---|
| Chronological age | years | — |
| Serum albumin | g/L | 35–50 |
| Creatinine | µmol/L | F 45–90 · M 60–110 |
| Fasting glucose | mmol/L | 3.9–5.5 |
| CRP (ideally hs-CRP) | mg/L | < 3 (optimal < 1) |
| Lymphocytes (%) | % | 20–40 |
| MCV (mean corpuscular volume) | fL | 80–100 |
| RDW-CV | % | 11.5–14.5 |
| Alkaline phosphatase (ALP) | U/L | 40–130 |
| White blood cells (WBC) | 10³/µL | 4.0–10.0 |
Practical tip: an annual check-up including FBC + CRP + fasting glucose + albumin + creatinine + ALP already contains 8 of the 9 values. Just ask your lab for the differential white cell count (for lymphocyte %) and the RDW-CV (usually reported automatically with the FBC).
PhenoAge vs epigenetic clocks: which one?
| Criterion | PhenoAge (Levine 2018) | Epigenetic clocks (DNAm) |
|---|---|---|
| Cost | €0 (covered blood panel) | €150–500 |
| Sample | Standard blood panel | Saliva or specific blood draw |
| Prescription | Your GP | Direct-to-consumer purchase |
| Method | Gompertz regression on 9 biomarkers | DNA methylation across 350+ CpG sites |
| Reproducibility | 2–5% between-lab variability | 1–3% intra-individual variability |
| Sensitivity to interventions | Moderate (3–6 months) | High (DunedinPACE within 6 weeks) |
| Independent validation | UK Biobank, Framingham, Rotterdam | Variable by test |
| Availability in Europe | Universal | Limited, mostly via US labs |
Pragmatic take: for annual tracking and monitoring of an intervention (diet, exercise, weight loss, supplementation), PhenoAge offers an excellent cost-to-information ratio. Epigenetic clocks remain the gold standard for research and advanced longevity protocols.
How to interpret your result
The calculator produces four values:
- Chronological age: your actual age.
- PhenoAge: your estimated biological age based on biomarkers.
- Phenotypic age acceleration (PhenoAgeAccel) = PhenoAge − chronological age. The most informative metric.
- 10-year mortality risk: a population-level epidemiological probability, not an individual prognosis.
Indicative reading grid for acceleration:
- ≤ −3 years: very favourable biological profile.
- −3 to 0 years: favourable, biologically younger than your age.
- 0 to +3 years: neutral, within the population average.
- +3 to +6 years: vigilance signal — review out-of-range biomarkers.
- > +6 years: alert signal — clinical discussion with your doctor is recommended.
Important limitations
- Population-level tool, not individual. Coefficients come from a US cohort, mostly of European descent, and have not been recalibrated for French, North African or other populations.
- Sensitive to transient states. A recent infection (elevated CRP), stroke, surgery, pregnancy or dehydration can distort the result. Sample at least 4–6 weeks away from any acute event.
- Misses some risks. The formula does not capture body composition, cardiorespiratory fitness (VO2max), sarcopenia or psychosocial factors. PhenoAge complements — but never replaces — a full clinical work-up.
- Ceiling and floor effects. At the extremes of the distribution, estimates become less reliable.
- No individual longitudinal validation. Within-person sensitivity to change after intervention remains modest (minimum 3–6 months recommended).
- Diagnoses no disease. An accelerated PhenoAge warrants a holistic review of lifestyle, not a diagnosis.
What to do if your biological age is accelerated?
Interventions validated to reduce phenotypic acceleration in the literature cover the classic evidence-based longevity pillars:
- Regular physical activity — endurance (zone 2, 150–180 min/week) + resistance training (2–3 sessions/week). Documented effects on CRP, glucose and lymphocytes.
- Mediterranean-style or plant-forward diet — reduces CRP, improves glucose handling and albumin.
- Quality sleep — 7–9 hours with consistent timing. Direct impact on systemic inflammation.
- Weight and visceral fat management — strongly correlates with ALP, glucose and CRP.
- Smoking cessation and alcohol moderation — reduces RDW, ALP and inflammation.
- Regular medical follow-up — address underlying conditions (hypertension, diabetes, dyslipidaemia, hypothyroidism).
Open source & transparency
The full source code of the calculator is open and auditable:
- GitHub repo: github.com/JETPOD/phenoage-calculator
- Live demo: jetpod.github.io/phenoage-calculator
- French version: Version française
- Licence: CC BY-NC-SA 4.0 (free non-commercial reuse with attribution)
Scientific references
- Levine ME, Lu AT, Quach A, Chen BH, Assimes TL, Bandinelli S, et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging (Albany NY). 2018;10(4):573-591. DOI: 10.18632/aging.101414
- Liu Z, Kuo PL, Horvath S, Crimmins E, Ferrucci L, Levine M. A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV. PLOS Medicine. 2018;15(12):e1002718. DOI: 10.1371/journal.pmed.1002718
- Kuo CL, Pilling LC, Liu Z, Atkins JL, Levine ME. Genetic associations for two biological age measures point to distinct aging phenotypes. Aging Cell. 2021;20(6):e13376. DOI: 10.1111/acel.13376
- Belsky DW, Caspi A, Corcoran DL, et al. DunedinPACE, a DNA methylation biomarker of the pace of aging. eLife. 2022;11:e73420. DOI: 10.7554/eLife.73420
- Lu AT, Quach A, Wilson JG, et al. DNA methylation GrimAge strongly predicts lifespan and healthspan. Aging (Albany NY). 2019;11(2):303-327. DOI: 10.18632/aging.101684
Medical disclaimer — This tool is an educational epidemiological instrument. It does not replace medical advice, diagnosis or treatment. If you have any concerns about your blood results or your health, consult your physician. PhenoAge is a population-level risk indicator, not an individual prognosis.
Article written by Dr Jean-Etienne Podik, public health physician. Last updated 26 June 2026.
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