Calculators from Precursor
Free tools built on published research, in Australian units, with the method shown rather than hidden. Each one explains what it measures, where the evidence comes from, and what it cannot tell you. No sign-up, and nothing you enter is stored.
Why these calculators are free
Useful first, honest about the limits
Most health calculators online exist to capture an email address. These do not ask for one, and nothing you type is sent anywhere. They run entirely in your browser.
What they can do is give you a defensible estimate from real published research. What they cannot do is measure anything, diagnose anything, or replace a conversation with your doctor. Every calculator here says so plainly, on its own page, along with what it is actually built from.
Three tools, three inputs
Use the blood marker calculator if you have had a blood test in the past year. It works from nine values on a standard pathology report and uses the published PhenoAge method.
Use the lifestyle calculator if you do not have recent bloods. It estimates from five habits linked to life expectancy and takes two minutes.
Use the BRI calculator if you want to measure central body shape from waist and height. Weight is optional, and the result is scored against Australian waist guidance.
Published models, shown working
Most health calculators online are black boxes. You enter numbers, a result appears, and nothing explains where it came from. When researchers at the University of Sydney scanned twenty biological age calculators, fewer than half explained the algorithm behind the result, and the same profile produced answers thirty years apart depending on which tool was used.
Ours work differently. Each one names the study it is built on and links the paper. Each one uses Australian units, so there is nothing to convert. Each one is reviewed by a practising clinician. And each one shows you the calculation, factor by factor, so you can judge the result rather than take it on faith.
We are also upfront about what they cannot do. None of these is a medical test or a diagnosis, and every one of them has a limitations section that says where the evidence stops.
Nothing you enter is stored
Every calculator here runs entirely in your browser. There is no sign-up, no email capture, and the values you type are never sent to us or saved anywhere.
