Biological Age Calculator
This calculator gives an educational estimate using a published research method. It is not a medical test, a diagnosis, or medical advice, and it does not replace seeing a doctor. Talk to your GP about what your blood results mean for you.
One known limitation of the method: it tends to return a number below your actual age, and that gap widens as you get older. Two people with identical bloodwork will see a bigger difference at 70 than at 30. Read your result as a starting point to track over time rather than as a score to compare against other people.
Where to find these numbers
Every value this calculator asks for comes from two routine panels your GP can order: a full blood count and a general chemistry panel including liver function. If you have had bloods done in the last year, the numbers are almost certainly already on that report.
Enter the values exactly as your pathology report shows them. The calculator uses Australian units throughout, so there is nothing to convert.
Chronological age counts birthdays. Everyone the same age has exactly the same number.
Biological age tries to answer a harder question: how is this particular body actually tracking? Two people who turn fifty on the same day can have meaningfully different cardiovascular function, inflammation, kidney function and immune profiles. Biological age is an attempt to put a single number on that difference, using measurable markers instead of a birth certificate.
It is a research tool, not a clinical diagnosis. A biological age above your chronological age is not a verdict and it is not a prediction about you personally. It is a signal, drawn from population data, that some of your markers are sitting where older people's markers usually sit.
Signals are useful precisely because they arrive before symptoms do.
THE METHOD
How this calculator works
WHAT THE MODEL USES
The nine markers
These nine were selected statistically, from a much larger pool, as the routine markers that together best predicted mortality risk. All of them come from two standard panels your GP can already order.
TWO DIFFERENT METHODS
PhenoAge vs DNA methylation
When people talk about biological age, they are usually talking about one of two different things, and the difference matters more than most articles admit.
Blood marker methods like PhenoAge use standard pathology results. They are cheap, repeatable, and the tests are already part of routine care. The trade-off is that they infer ageing from the downstream consequences of it, the things that show up in your blood chemistry.
DNA methylation methods, sometimes called epigenetic clocks, measure chemical marks on the DNA itself. They look closer to the underlying biology, which is why they are often described as the more advanced approach. The trade-offs are cost, usually several hundred dollars in Australia, limited availability, and much less consistency between providers than the marketing suggests.
This calculator uses the blood marker method. We chose it deliberately: the inputs are tests any GP can order, the model is published and you can read it, and you can repeat it as often as you have bloods done, which matters because the trend is more informative than any single reading.
WHAT THE EVIDENCE SAYS
What moves these markers
A number on its own is not much use. The more useful question is what the research says about the things that shift these particular markers.
Two honest caveats before the list. Most of this evidence is associational, meaning it shows that people who do these things tend to have better marker profiles, not that doing them will change yours by a specific amount. And a marker moving is not the same as ageing slowing down. Treat the below as reasonable, well-supported directions rather than a protocol.
Cardiorespiratory fitness. Of everything on this list, this has the strongest association with long-term mortality risk. It is also one of the few things that shows up across several of these markers at once rather than just one.
Inflammation. hs-CRP is the most changeable marker in the model, and also the most easily confounded. It responds to infection, injury, sleep, body composition and smoking. That volatility is why a single reading says little and a pattern says more.
Metabolic health. Fasting glucose responds to diet composition, body composition and activity, and it tends to move slowly and steadily rather than in jumps.
Sleep. Consistently short or poor-quality sleep is associated with higher inflammatory markers and worse metabolic measures. It is the most commonly overlooked input on this list.
Alcohol. Affects liver markers directly, including albumin and ALP, both of which feed this model.
Things you cannot change. Genetics, age itself, and some conditions all influence these markers. A higher estimate is not a personal failure, and framing it that way is both unkind and inaccurate.
What to do with this. If your estimate came out higher than your actual age, the useful next step is not a supplement or a protocol. It is a conversation with your GP about which markers sat outside their reference range and whether anything warrants following up. This calculator can point at a marker. It cannot tell you why yours is where it is.
TAKE CONTROL OF YOUR HEALTH
This calculator works with nine markers you happened to have on hand. A proper screen looks wider, tracks change over time, and puts a clinician between the numbers and your decisions.
WHAT THIS CANNOT TELL YOU
Honest limitations
It is a population estimate, not a personal prediction. The model was built by observing what happened to large groups of people. It cannot tell you what will happen to you.
It reflects one moment. Blood markers move. An hs-CRP taken while you are fighting a cold will read high and push your estimate up, which says something about that week, not about your decade.
It was not developed on an Australian population. PhenoAge was built from US survey data. The markers and biology are the same, but no model is perfectly transportable.
It is not a diagnosis. If a marker sits outside its reference range, that is a conversation to have with your GP, not something this calculator can interpret for you.
A younger result is not a clean bill of health. Nine markers is nine markers. Plenty of serious conditions would not register here at all, which is exactly why screening looks at more than a blood panel.
TRACKING OVER TIME
How often to check
One reading is a data point. Several are a trend.
A single biological age estimate tells you very little. Markers move week to week, and a result taken while you are fighting a cold will read differently from one taken a month later.
What is actually informative is the same markers measured the same way over years. Most people having routine bloods annually will have everything they need to recalculate each time. If you are going to take one thing from this page, take that: the direction of travel matters more than the number.
WHAT IT COSTS
What testing costs in Australia
What biological age testing costs in Australia
This calculator is free, and if you already have recent bloods it costs you nothing but the time to type nine numbers in.
Standard blood panels. The tests this calculator uses are routine. If your GP orders them for a clinical reason, they are typically covered by Medicare. Ordered privately without a clinical indication, expect a modest out-of-pocket cost, and your GP or pathology provider can tell you exactly what applies.
Epigenetic tests. DNA methylation biological age tests from Australian providers generally run several hundred dollars, and often closer to a thousand once a blood draw is included. Whether that is worth it depends on what you plan to do with the number.
Comprehensive screening programs. Preventive health programs that bundle bloods, imaging and clinician review sit higher again, and are a different proposition from a single test. They are buying you interpretation and follow-up, not just a result.
The honest summary. If you want a number, this calculator gives you one for free. If you want to know what your markers actually mean for you, that requires a clinician, and that is what you are paying for in any of the paid options above.
SOURCES & SUPPORTING EVIDENCE
Sources
The model
PLoS Medicine
A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV
https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002718PLoS Medicine
Correction: A new aging measure captures morbidity and mortality risk across diverse subpopulations from NHANES IV
https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002760Health Promotion Journal of Australia
Biological age calculators to motivate lifestyle change: Environmental scan of online tools and evaluation of behaviour change techniques
https://onlinelibrary.wiley.com/doi/abs/10.1002/hpja.671
Supporting evidence
Scientific Reports
The relationship between red cell distribution width and all-cause and cause-specific mortality in a general population
https://www.nature.com/articles/s41598-019-52708-2The Lancet
C-reactive protein concentration and risk of coronary heart disease, stroke, and mortality: an individual participant meta-analysis
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(09)61717-7/fulltextGenome Biology
DNA methylation age of human tissues and cell types
https://link.springer.com/article/10.1186/gb-2013-14-10-r115Mayo Clinic Proceedings
Objectively assessed cardiorespiratory fitness and all-cause mortality risk: a systematic review and meta-analysis
https://www.mayoclinicproceedings.org/article/S0025-6196(22)00133-1/abstract
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