Short answer: yes, and for understanding one result it is genuinely very good. Use it. The limitation is different from the one most people assume, and it only matters if you intend to measure change over time.
Upload a lab PDF to ChatGPT, Gemini or Claude and ask what a result means, and you will get a clear, well-organised explanation — often better written than most medical sites, and with the obvious follow-up questions anticipated.
It also handles markers no fixed tool covers, explains the biochemistry at whatever depth you ask for, and answers immediately without data entry. For a one-off question about a single result, that is the better tool, and we would rather say so than pretend otherwise.
A language model produces a plausible response, not a computed one. Ask the same question twice and the wording, emphasis and often the number itself will differ. That variability is a feature when you are exploring an idea and a defect when you are trying to measure something.
The problem is not accuracy. It is reproducibility. If you score the same panel in March and again in September and the method quietly changed in between, the difference you observe is partly the method and partly you — and you cannot tell which is which.
Measuring change requires the instrument to hold still. That is the entire distinction.
This tool computes a score rather than generating one. The scoring model is published in full, versioned when it changes, and covered by an automated test suite that asserts specific properties on every build.
Those properties are not marketing claims; they are tests that fail the build if violated. They are the practical difference between a calculator and a conversation.
repeated scoring of the same input is deterministicimproving a single biomarker never worsens the compositehealthier panels always score betteran identical perfect panel scores the same regardless of agescoring is pure — inputs are not mutatedblank, whitespace and non-numeric values are ignored, not scored as zerodials with no entered markers are omitted entirelyLongevity Score is bounded to 0..100| Job | Better tool | Why |
|---|---|---|
| Explaining one marker in depth | Chat model | Better — conversational, unlimited scope |
| Answering a question at 2am | Chat model | Better — instant, no data entry |
| Same answer twice | Fixed engine | Tested on every build |
| Tracking a change over two years | Fixed engine | Requires a stable method |
| Published, versioned methodology | Fixed engine | Chat models cannot show their reasoning reliably |
| Clinically reviewed thresholds | Fixed engine | Named reviewer, dated |
| Handling a partial panel consistently | Fixed engine | Blanks excluded, weights renormalised |
| Covering a marker we do not score | Chat model | Better — no fixed list |
The sensible division is straightforward. Use a chat model to understand what a marker means, explore a mechanism, or draft questions for your doctor. Use a fixed instrument to establish a baseline, score consistently, and track whether an intervention actually worked.
They are complementary. The mistake is using a conversational model as a measuring device, because it will answer confidently either way and give you no signal that it has drifted.
Whatever tool you use, ask where its reference ranges come from. A number is only as good as the threshold it is compared against, and most tools — chat models included — will not tell you, because the answer is an average of whatever was in the training data.
Our ranges, weights and handling of missing values are published on the methodology page, clinically reviewed, and attributable to named people. You are entitled to disagree with them; you should at least be able to see them.
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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.