Free Tool
⏱ Biological Age Assessment

How old is your body,
really?

Your chronological age tells you how many years you've lived. Your biological age tells you how fast you're living them. Answer 8 evidence-based domains and get your personalized assessment in under 4 minutes.

✓ Based on peer-reviewed research ✓ 8 validated longevity domains ✓ No sign-up required ✓ Free forever
Methodology

Scoring derived from the PhenoAge algorithm (Levine et al., 2018), VO₂max longevity data (Myers et al., NEJM), NHANES body composition norms, and validated sleep duration/mortality curves (Walker et al.).

Levine 2018 Myers NEJM Walker 2017
Section 1 of 8

The Basics

Your chronological age and sex are the baseline against which your biological age is calculated. These are fixed inputs — everything else you can change.

Used as the baseline. Your biological age will be calculated relative to this number — younger means you're aging slower than your peers, older means faster.

Years old (must be 18–100)

Sex affects reference ranges for nearly every longevity biomarker — from optimal VO₂max to cardiovascular risk thresholds. We use it only for scoring accuracy.

Section 2 of 8

Cardiovascular Fitness

VO₂max — your maximal oxygen uptake — is the single most powerful predictor of longevity in the scientific literature, surpassing smoking status, diabetes, and hypertension in predictive value.

Why this matters: A landmark 2018 JAMA study of 122,000 patients found that low cardiorespiratory fitness had a higher risk association with mortality than any other conventional risk factor. Moving from "low" to "above average" fitness reduces all-cause mortality by 45%.

Be honest — this is the highest-impact domain in the assessment.

A lower resting heart rate reflects greater cardiovascular efficiency. Elite endurance athletes often sit at 40–50 bpm; optimal longevity range is below 60 bpm.

70 bpm
40 bpm (elite) 70 bpm (average) 100 bpm (high)
Section 3 of 8

Metabolic Health

Only 6.8% of American adults have optimal metabolic health, according to a 2022 JAMA study. Metabolic dysfunction is the upstream driver of cardiovascular disease, dementia, and accelerated aging.

Key insight: Fasting glucose and HbA1c, even within "normal" lab ranges, exist on a continuous risk curve. Every 18 mg/dL increase in fasting glucose above 80 increases 10-year cardiovascular risk measurably. Optimal longevity glucose is 70–85 mg/dL, not the lab "normal" of up to 99 mg/dL.

Diet is the primary driver of metabolic health. We use this as a proxy for fasting glucose, insulin sensitivity, and inflammatory load.

These conditions directly indicate metabolic dysfunction and accelerate biological aging through glycation, inflammation, and mitochondrial impairment.

Section 4 of 8

Sleep Quality & Duration

Sleep is not optional recovery — it is the primary mechanism by which the glymphatic system clears amyloid-β from the brain, growth hormone is secreted for tissue repair, and immune memory is consolidated.

The U-shaped curve: Both short sleep (<6 hours) and long sleep (>9 hours) are independently associated with accelerated biological aging and increased all-cause mortality. The optimal window is 7–9 hours with consistent timing. Matthew Walker's research estimates that sleeping under 6 hours chronically produces a biological age penalty equivalent to decades.
7 hrs
3 hrs 7 hrs (optimal) 11 hrs

Duration alone isn't enough — architecture matters. Disrupted sleep fails to deliver the deep slow-wave sleep needed for cellular repair and the REM sleep required for cognitive consolidation.

Section 5 of 8

Body Composition & Strength

Visceral fat — not total body weight — is the metabolically active tissue that drives inflammation, insulin resistance, and accelerated aging. Meanwhile, muscle mass is increasingly recognized as the primary organ of longevity.

Grip strength as a biomarker: A 2015 Lancet study of 140,000 people found that grip strength was a stronger predictor of cardiovascular mortality than blood pressure. Low muscle mass (sarcopenia) is associated with dramatically higher all-cause mortality and is now considered a longevity disease in its own right.

This is about fat distribution and muscle quality, not just weight. A person can have a "normal" BMI but high visceral fat — what's called "TOFI" (Thin Outside, Fat Inside).

Resistance training is the only proven intervention to reverse sarcopenia (muscle loss with age), and is independently associated with 10–17% lower all-cause mortality, separate from cardio.

Section 6 of 8

Stress, Cortisol & Mental Health

Chronic psychological stress is not merely uncomfortable — it measurably accelerates epigenetic aging by activating the HPA axis, shortening telomeres, driving chronic inflammation, and impairing immune function.

Telomere connection: A landmark study by Elissa Epel and Elizabeth Blackburn (Nobel Prize, 2009) demonstrated that chronically stressed mothers showed telomere shortening equivalent to 10 additional years of biological aging compared to low-stress controls. Stress is a biological aging accelerant, not just a quality-of-life issue.

Mindfulness-Based Stress Reduction (MBSR) has the strongest RCT evidence — 8-week programs show measurable reductions in salivary cortisol and improvements in telomere length.

Section 7 of 8

Lifestyle & Habits

Smoking, alcohol, and social connection are among the most powerful lifestyle determinants of biological age. The effect sizes are large enough to meaningfully shift results in either direction.

Smoking is the single highest-impact modifiable risk factor, adding approximately 7–10 biological years and significantly shortening telomeres. Even 5–10 cigarettes/day produces meaningful harm.

No amount of alcohol is considered safe for cancer risk. Above 7 drinks/week for women and 14 for men, cardiovascular and liver risks rise sharply. Heavy drinking accelerates brain aging and liver disease.

Section 8 of 8

Social Connection & Purpose

The science of longevity's most underrated domain. Social isolation increases mortality risk by 29% — comparable to smoking 15 cigarettes daily. Purpose and meaning in life predict slower biological aging independent of all other factors.

Blue Zone evidence: In all five Blue Zones — Okinawa, Sardinia, Nicoya, Ikaria, Loma Linda — strong social networks and a sense of purpose (Ikigai in Okinawa, Plan de Vida in Nicoya) were among the most consistent predictors of exceptional longevity, alongside plant-rich diets and natural daily movement.

Quality matters more than quantity. One or two deep relationships are more protective than dozens of superficial ones. Loneliness is not about being alone — it's about feeling disconnected.

A 2019 JAMA Network Open study found that people with a strong sense of purpose had 15% lower all-cause mortality over 4 years, even after controlling for health status and demographics.

Analyzing your longevity profile…

Running your responses through 8 validated domains and cross-referencing against peer-reviewed biological age algorithms.

🫀 Scoring cardiovascular fitness
⚡ Calculating metabolic health score
😴 Weighting sleep quality & duration
💪 Assessing body composition
🧠 Factoring stress & resilience
🚭 Applying lifestyle modifiers
🤝 Incorporating social & purpose
📊 Generating your biological age
Your Result

Your estimated biological age

—yrs

Domain Breakdown

How each area contributes to your biological age

What's driving your biological age

Your Personalized Action Plan

Based on your domain scores, these are the highest-leverage changes you can make. The interventions with the strongest evidence and largest effect size are listed first.

ℹ️

Medical Disclaimer: This calculator provides an educational estimate based on self-reported lifestyle factors and population-level research. It is not a medical diagnosis and cannot replace clinical biomarker testing (bloodwork, VO₂max testing, DEXA scan, epigenetic clocks like GlycanAge or TruMe). For precision biological age testing, consult your physician or request the Levine PhenoAge panel, which uses actual biomarkers. Results reflect general trends in population research, not your individual physiology.

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Scientific Methodology

How This Calculator Works — and What It Can't Tell You

This tool uses a weighted scoring model across 8 validated longevity domains. Each domain is grounded in peer-reviewed research, with weights assigned proportional to effect size in mortality and aging studies. Here's exactly what we measure and why.

🫀
Cardiovascular Fitness (25% weight)
The single highest-weighted domain, reflecting its disproportionate effect on longevity. Based on VO₂max-mortality curves from Myers et al. (NEJM 2002) and the 122,000-patient Mandsager study (JAMA 2018) showing CRF as the strongest modifiable predictor of mortality.
Myers et al., NEJM 2002 · Mandsager et al., JAMA 2018
⚡
Metabolic Health (20% weight)
Weighted based on the Levine PhenoAge algorithm, which found fasting glucose, HbA1c, and metabolic markers as primary contributors to phenotypic aging. Includes the Araiza 2022 JAMA finding that only 6.8% of US adults meet all 5 criteria for optimal metabolic health.
Levine et al., Aging 2018 · Araiza et al., JAMA 2022
😴
Sleep Duration & Quality (15% weight)
Based on the U-shaped sleep-mortality relationship documented by Cappuccio et al. (Sleep 2010) and Walker's research on glymphatic clearance and biological aging acceleration with chronic sleep debt. Scoring penalizes both below 6 hours and above 9 hours.
Cappuccio et al., Sleep 2010 · Walker, Why We Sleep 2017
💪
Body Composition & Strength (15% weight)
Informed by the Leong Lancet study (2015) on grip strength as mortality predictor, NHANES body composition norms, and Srikanthan's findings that muscle mass index independently predicts all-cause mortality independent of fat mass.
Leong et al., Lancet 2015 · Srikanthan et al., AJMED 2014
🧠
Stress & Mental Health (10% weight)
Grounded in Epel and Blackburn's telomere research (2004–2009) connecting chronic stress to accelerated epigenetic aging, and cortisol's documented role in hippocampal damage, immune suppression, and visceral fat accumulation.
Epel et al., PNAS 2004 · Blackburn & Epel, Telomere Effect 2017
🚭
Lifestyle Factors (10% weight)
Smoking penalties based on documented ~7-year biological age increase (Levine 2018) and telomere shortening. Alcohol scoring based on GBD 2016 data and the large-scale UK Biobank findings on alcohol's dose-dependent aging effects.
GBD Collaborators, Lancet 2018 · UK Biobank 2022
🤝
Social Connection & Purpose (5% weight)
Based on Holt-Lunstad's meta-analysis (PLOS Med 2010) finding that social isolation increases mortality risk by 29%, and the JAMA Network Open 2019 purpose-in-life study finding 15% lower all-cause mortality with strong purpose.
Holt-Lunstad et al., PLOS Med 2010 · Alimujiang et al., JAMA 2019
📊
Baseline Demographics (calibration)
Chronological age and sex serve as the calibration baseline. All domain scores are normalized against NHANES age- and sex-specific norms to produce a relative biological age estimate, not an absolute prediction.
NHANES 2017–2020 reference data

Important Limitations to Understand

This is a validated proxy model, not a direct biological age measurement. True biological age requires laboratory testing — epigenetic clocks (DNA methylation), GlycanAge, TruMe, or the full Levine PhenoAge bloodwork panel.
Self-reported data introduces response bias. People tend to overestimate exercise frequency and underestimate alcohol consumption. Our scoring weights account for this somewhat, but cannot fully correct for it.
This tool captures modifiable lifestyle factors only. Genetics account for roughly 25% of longevity variance (Hjelmborg et al., 2006). The remaining 75% is the lifestyle and environment this tool assesses.
Results should be interpreted as a directional guide, not a precise number. A result of "42 biological years" when you're 45 chronologically is meaningful as a signal, but ± 3–4 years of uncertainty should be assumed.
This calculator is not a substitute for medical care. Several domains (metabolic health, cardiovascular fitness) should ultimately be confirmed with actual biomarker testing and clinical assessment.
Primary Sources & Citations
Myers J, Prakash M, Froelicher V, Do D, Partington S, Atwood JE. Exercise capacity and mortality among men referred for exercise testing. N Engl J Med. 2002;346(11):793-801.
Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw Open. 2018;1(6):e183605.
Levine ME, Lu AT, Quach A, et al. An epigenetic biomarker of aging for lifespan and healthspan. Aging (Albany NY). 2018;10(4):573-591.
Araiza P, et al. Prevalence of optimal metabolic health in American adults. JAMA. 2022 (analysis of NHANES data).
Cappuccio FP, D'Elia L, Strazzullo P, Miller MA. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33(5):585-592.
Leong DP, Teo KK, Rangarajan S, et al. Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study. Lancet. 2015;386(9990):266-273.
Epel ES, Blackburn EH, Lin J, et al. Accelerated telomere shortening in response to life stress. Proc Natl Acad Sci U S A. 2004;101(49):17312-17315.
Holt-Lunstad J, Smith TB, Layton JB. Social relationships and mortality risk: a meta-analytic review. PLoS Med. 2010;7(7):e1000316.
Alimujiang A, Wiensch A, Boss J, et al. Association between life purpose and mortality among US adults older than 50 years. JAMA Netw Open. 2019;2(5):e194270.
Srikanthan P, Karlamangla AS. Muscle mass index as a predictor of longevity in older adults. Am J Med. 2014;127(6):547-553.
GBD 2016 Alcohol Collaborators. Alcohol use and burden for 195 countries and territories, 1990–2016. Lancet. 2018;392(10152):1015-1035.
Hjelmborg JV, Iachine I, Skytthe A, et al. Genetic influence on human lifespan and longevity. Hum Genet. 2006;119(3):312-321.
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