Explore your health across eight systems, from metabolism to strength, using the information you already have.
Based on 8 Dials of Longevity · Estimates, not a diagnosis · How your data is handled
In the starting example, 7 of the eight dials run younger than this person's actual age of 45 — but inflammatory is 7 years older, the only dial that is. A single averaged number would have reported 41 and said nothing about why. See what moves it →
Enable JavaScript to drag this — or try the real What-If Simulator with your own numbers.
Start with a question, a measurement, or the bigger picture. You do not need a full lab panel to explore.
Explore what individual biomarkers measure and how they fit into your health.
Explore biomarkers → 02 / MoveLearn about the floor-based sitting-rising test and its safety limitations.
Explore the test → 03 / ConnectDiscover how different parts of your health contribute to the bigger picture.
Explore the dials →Use a calculator or explore a reference, then go deeper when you are ready.
Explore what fasting insulin and glucose can suggest together.
Open calculator → Calculator / Body compositionPut two simple measurements in context with a tape measure.
Open calculator → Physical functionLearn about the floor-based test and when not to attempt it.
Explore the test →Use the dashboard as a starting point for informed conversations and tracking over time.
Start with results and measurements you already have.
Open the assessment →Explore the eight systems behind your results.
Explore the dials →Consider practical next steps and questions for your clinician.
Explore the guide →After an assessment, explore progress and optional discussion reminders.
Open the assessment →There is no shortage of biological age tools. Four things separate this one, and all four are checkable rather than claimed.
A single age hides where you are actually ageing — in the example above, the composite is 41, and that alone would read as good news. Inflammatory at 52 is the system that actually needs attention, and an average cannot tell you that.
Thresholds, weights and rules are written down. A health number you cannot interrogate is not worth much.
Scoring is computed, not generated, and tested on every build to return identical results for identical input. You cannot measure change with an instrument that moves.
Blank values are excluded, never counted as zero or quietly assumed normal. Dials with no data are dropped and the rest reweighted, so a partial panel gives a real score rather than a padded one.
Each is scored independently from its own biomarkers, then weighted into one Longevity Score. The weights are fixed, published, and sum to exactly 1.0 — the bar shows each dial's share.
Start with structural age if you only read one — it carries the most weight and predicts independence later in life better than any single lab value.
Most people assess their health the same way: they feel fine, so they assume they are fine. That works right up until it does not. Feeling fine is a lagging indicator — it reports failure after the margin is already gone.
The alternative is to treat healthspan as something with measurable specifications. Not lifespan, which you cannot steer directly, but the number of years the machine runs well: strength, cognition, metabolic control, independence.
An illustration, not a projection: two lives ending at the same age with different numbers of good years. The gap — not lifespan — is what the eight dials are scored against. This tool does not predict either figure.
Complex systems rarely fail from one dramatic event. They fail from slow drift — pressure that is slightly too high for twenty years, insulin that creeps up, muscle that is never loaded, inflammation nobody measured.
Drift is invisible without telemetry, and it is cheap to correct early and expensive to correct late. That is the entire argument for measuring before anything hurts.
An illustration of a shape, not a measured curve. The point is that the silent window is long: drift is measurable for years or decades before anything is felt, and everything cheap to fix happens inside it.
An epigenetic clock returns one number. It is interesting, but you cannot act on it — it does not tell you which system is drifting or which lever to pull.
Eight dials are scored independently, each from its own biomarkers, then weighted into one Longevity Score. The composite tells you where you stand; the dials tell you what to do about it. When they disagree, that disagreement is the most useful signal on the page.
Both score 42, using the engine’s real dial weights rather than a plain average. One of these people has a structural problem that a single biological age will never surface, and that is the entire reason for scoring eight dials separately.
Markers move on very different timescales, and confusing the two is the most common reason people conclude that nothing is working. Blood pressure responds in days. HbA1c is a 8–12 week average. A calcium score reflects years of accumulated exposure.
Steer with the fast signals. Audit with the slow ones. Each dial page sets out which is which, and how long each marker actually takes to move.
Each dot is one marker, coloured by its dial. Retesting an audit metric after three weeks measures noise — which is the most common reason people conclude that nothing is working.
The calculator runs in two modes. Short form shows a subset of scoring inputs and context-only fields, and Complete opens all of them. This is not a recommended screening panel. Either way, anything you leave blank is excluded rather than counted as zero.
Some inputs can be measured at home. The guide explains their limitations and the fall risk of the floor-based sitting-rising test.
How biological age is calculated, why these ranges are stricter than your lab's, what you can measure at home, and how your data is handled — see the frequently asked questions.
Wondering whether to just ask an AI instead? Fair question, and the honest answer is "for some things, yes" — here is where a chat model is better, and where it is not.
Based on 8 Dials of Longevity: An Engineering Framework for Measuring and Extending Healthspan by Steve Fayzulayev & Naomi Fayzulayev, FNP-C, MSN. Recent scoring revisions are clinically reviewed.
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.