Laboratory ranges and calculator scoring ranges serve different purposes. A result needs interpretation in the context of your own health and laboratory report.
A standard laboratory reference range is, in most cases, a statistical description: the central 95% of results from a reference population. It answers the question "is this result unusual?"
A reference interval alone does not determine whether an individual result is healthy or requires action. Clinical interpretation also considers decision thresholds and personal circumstances.
Laboratory reference intervals, clinical decision thresholds and calculator scoring ranges answer different questions. A reference interval is not always a diagnostic cutoff, and clinical decisions also depend on symptoms and personal history.
The calculator uses book-aligned scoring ranges for some inputs. They are model choices, not established individual treatment targets. Some inputs are shown for context only and are not scored.
| Marker | Longevity-optimised | Typical standard range |
|---|---|---|
| ApoB | < 60 mg/dL | ApoB is not always included in a standard lipid panel. |
| VO₂ Max | 45–60 mL/kg/min | VO₂ max is not routinely measured for everyone. |
| hs-CRP | < 1 mg/L | Commonly cited cardiovascular risk categories are under 1 mg/L, 1–3 mg/L and above 3 mg/L. |
| Fasting Insulin | < 5 µIU/mL | Fasting insulin reference intervals vary by laboratory and assay. |
| Lp(a) | < 30 nmol/L | Lp(a) is not part of a standard lipid panel and is rarely measured unless specifically requested. |
| IGF-1 | 120–220 ng/mL | Standard reference ranges are age-banded and vary noticeably by lab and sex — a widely used commercial range for the 40s and 50s spans roughly 53 to 298 ng/mL across both sexes combined, with each lab publishing its own narrower band by decade and sex on the report itself. |
| HbA1c | 4–5.2 % | For nonpregnant adults, an A1c below 5.7% is generally considered normal for diabetes screening, 5.7–6.4% is in the prediabetes range, and 6.5% or above is in the diabetes range. |
| Grip Strength | 51–70 kg | Grip strength is not part of routine care outside geriatrics, where it is used mainly to screen for sarcopenia and frailty — that is, to identify people already in decline rather than to track reserve. |
| HRV | ≥ 60 ms | HRV is not measured in routine care. |
| Vitamin D | Context only — not scored | Interpretation of 25-hydroxyvitamin D depends on the laboratory, your health and the reason for testing. |
| Homocysteine | Context only — not scored | Reference intervals vary by laboratory. |
| Blood Pressure | 90–115 mmHg | Guidelines have moved: 140/90 mmHg was the hypertension threshold for decades, and US guidance now sets it at 130/80 mmHg, with 120–129 systolic called "elevated". |
| Fasting Glucose | 70–90 mg/dL | Under 100 mg/dL (5.6 mmol/L) is reported as normal. |
| Triglycerides | < 80 mg/dL | Under 150 mg/dL (1.7 mmol/L) is reported as normal on essentially every lab panel worldwide. |
| Carotid IMT | < 0.6 mm | No single illustrative reference interval is shown. |
| Resting Heart Rate | 40–60 bpm | 60–100 beats per minute is the normal range quoted almost universally, and it has barely changed in decades. |
| Ferritin | 40–100 ng/mL | Reference ranges are extremely wide — commonly about 30–400 ng/mL for men and 15–200 ng/mL for women, varying by laboratory. |
| eGFR | ≥ 90 mL/min/1.73m² | An eGFR below 60 mL/min/1.73 m² can be a sign of kidney disease, but one result alone does not establish chronic kidney disease. |
| Uric Acid | 2.5–5 mg/dL | Roughly 3.5–7.2 mg/dL for men and 2.6–6.0 mg/dL for women, varying by lab. |
| ALT | < 20 U/L | Upper limits of about 40–55 U/L for men and 33–45 U/L for women are typical, varying widely between laboratories. |
| Testosterone | 600–900 ng/dL | Reference intervals depend on the laboratory, assay and population. |
| TSH | 1–2.5 mIU/L | TSH reference intervals vary by laboratory, assay and population. |
| Morning Cortisol | Context only — not scored | Morning cortisol reference intervals vary by laboratory, method and collection time. |
| Sleep Duration | 7–9 hrs | There is no laboratory range for sleep, which is precisely the problem — it is never measured in routine care and never appears on a results page. |
| Omega-3 Index | ≥ 8 % | Not offered by most laboratories and not part of any routine panel, so the overwhelming majority of people have never seen a number. |
| Non-HDL Cholesterol | < 100 mg/dL | Commonly flagged above 130 mg/dL, with 160 and above treated as high. |
| ApoA1 | ≥ 160 mg/dL | Where reported, roughly 110–180 mg/dL for men and 110–205 mg/dL for women. |
| Vitamin B12 | ≥ 400 pg/mL | Typically 200–900 pg/mL, with deficiency flagged only below about 200. |
| GGT | < 15 U/L | GGT reference intervals vary by laboratory and population. |
| Daily Steps | ≥ 9000 steps | "10,000 steps a day" is public-health folklore, not a research finding — it traces back to a 1960s Japanese pedometer marketed as manpo-kei, literally "10,000-step meter", a round number chosen for advertising. |
| Free Testosterone | 15–30 pg/mL | Reference intervals depend on the laboratory, assay method and population. |
| DHEA-S | 200–400 µg/dL | Most labs report DHEA-S against a reference interval that already shifts down with age — unlike testosterone or blood pressure, where one static range gets applied at every age. |
| Estradiol | 20–120 pg/mL | Most labs report roughly 10–40 pg/mL as the normal range for men, with no single number for women because the real range is cycle-dependent — commonly cited as about 19–144 pg/mL in the follicular phase, rising to a mid-cycle ovulatory peak that can exceed 350 pg/mL, falling back to roughly 56–214 pg/mL in the luteal phase, and dropping to a much lower postmenopausal baseline unless a woman is on hormone therapy. |
| WBC | 3.5–6 ×10³/µL | The standard laboratory range is wide — typically 4.5 to 11.0 ×10³/µL — because it has to safely contain everyone from someone fighting off a cold to someone with no infection at all. |
Optimised ranges are the ones used by the Longevity Score calculator. Standard ranges vary between laboratories and assays — check the range printed on your own report.
The calculator's reviewed optimal target is 2–5 µIU/mL. The book describes a range below 8–10; the calculator uses the stricter target.
Laboratory intervals and assays vary. A fasting insulin result alone does not diagnose insulin resistance; discuss it with your clinician alongside glucose, HbA1c and your health history.
A value outside an optimised range is not a diagnosis, and it is not a reason to change medication. It means there may be room to improve, from a longevity perspective, in a system that is not currently failing.
It also does not mean your clinician is wrong. If a result here concerns you, discuss it with them rather than acting on the score alone. The lab discussion list can help prepare for that conversation.
They are drawn from published cohort and outcome literature, clinical practice in preventive medicine, and the 8 Dials of Longevity framework. The methodology sets out how each is applied, how markers are weighted, and what the model explicitly does not claim.
See where you sit on all 8 dials →Choose a question. Answers come from this site, and nothing you open is sent anywhere.
Chronological age counts birthdays. Biological age estimates how old your body appears to be functioning, based on measurable biomarkers. Two people born the same year can differ by a decade or more in vascular stiffness, insulin signalling or cardiorespiratory fitness. Biological age makes that gap explicit — and unlike your birthday, it can move in either direction.
Each biomarker you enter is scored against longevity-optimised reference ranges and grouped into one of eight dials. Every dial produces its own biological age, and those are combined using fixed weights into a single composite, then expressed as a Longevity Score from 0 to 100. The weighting reflects how strongly each system predicts healthspan: structural and vascular carry the most, hormonal the least.
No. The short form contains a subset of scoring inputs plus context-only fields, and you can leave any of them blank. It is not a recommendation to obtain tests. Missing values are excluded from the calculation — never treated as zero or as 'normal'. A dial with no scored data is dropped entirely and the remaining weights renormalise.
Some inputs can be measured without bloodwork. Blood pressure needs a home cuff and waist-to-height needs a tape measure. Wearable estimates vary; the floor-based sitting-rising test carries a fall risk and should only be attempted if safe.
Both terms describe what this tool does, and which one fits depends on what you are asking. "Anti-aging" is the term most people search, and loosely means anything aimed at slowing or reversing age-related decline — this tool fits that description if you score your dials and act on what you find. "Healthspan calculator" is the more precise term: healthspan is the number of years lived without serious chronic disease or disability, and that cannot be measured directly, so this tool scores eight systems that each function as an early-warning proxy for it. Either way, the method is the same: real biomarkers, published thresholds, no vanity-metric framing.
Several popular tools ask only about habits — exercise days, sleep hours, smoking, diet quality — and return a single precise-looking age. We looked at the research behind that approach and chose not to build it. Published studies do show real, individually-measured links between specific habits and epigenetic age acceleration, but those effect sizes come from different study populations, different DNA-methylation clocks and different measurement units. Adding them together into one number is not something the underlying research actually supports — it produces a precise-looking result built on an imprecise method. Our dials use direct physiological measurements instead: a real blood pressure reading, a real VO₂ max, a real ApoB value. Several dials score from home-measurable data alone with no quiz-guessing involved — see what you can measure without a blood test, above.
Standard reference ranges describe what is common in a general population, which now includes a great deal of metabolic dysfunction. They are tuned to flag disease, not to identify what is optimal for a long healthspan. A fasting insulin of 20 µIU/mL sits inside most labs' normal range and is strongly associated with insulin resistance. This tool uses longevity-optimised thresholds instead, so a flag here means room for optimisation — not a diagnosis.
For understanding a single result, do — a frontier chat model is genuinely good at that, often clearer than most medical sites, and it handles markers no fixed tool covers. The limitation is different from the one most people assume. A language model produces a plausible response rather than a computed one, so the same panel can score differently on different days. That is fine when exploring an idea and disqualifying when measuring change, because you cannot tell how much of a difference is you and how much is the method. Use both: a chat model to understand, a fixed instrument to track.
Biomarker values, assessment history and visit-preparation drafts are stored in your browser. The visit draft is separate from assessment exports and share links; copying or printing it can leave a copy outside the browser. There are no user accounts or third-party tracking. We keep anonymous usage totals on our own server, such as how many people reached a results screen on a given day; browsers sending Do Not Track or Global Privacy Control are not counted. Optional lab-report upload and AI coach features send data to Anthropic. Optional retest reminders send an email address, date and reminder label to our service and email provider. See our privacy policy for details.
No. It is an educational and personal-tracking tool. The estimates are not clinically validated and must not replace evaluation by a qualified healthcare professional. If a result concerns you — particularly kidney markers, blood pressure or ApoB — take it to a doctor rather than acting on it alone.