How this works, and what it cannot do

This tool is built to be honest about uncertainty rather than to flatter. Here is exactly how it produces a range.

The method

It starts from approximate UK age and sex-specific mortality rates, the actuarial baseline. It then adjusts those rates up or down using effect sizes drawn from the general direction of published health research, for factors such as smoking, weight, activity, alcohol, sleep, diet, social connection, family history, and diagnosed conditions.

Correlated factors, such as weight, diabetes, and blood pressure, are grouped so their shared risk is not counted more than once, a common flaw in simpler calculators. The total adjustment is capped within the range that real-world evidence supports, which is why no profile produces an implausibly high or low result. The adjusted mortality curve is then rebuilt and the tool reports the five-year band containing the median age at death.

Why a range, not a number

Two people identical on every input the tool collects can die decades apart. The variation within any profile is far larger than the difference between profiles. A single number would imply a precision that does not exist. The band is the honest width of what the statistics support.

What it cannot do

It cannot predict any individual outcome. It knows nothing about accidents, genetics beyond a single family-history question, or conditions you do not enter. The underlying figures are a defensible approximation, not validated clinical data, and should be treated as a prompt for reflection rather than a medical assessment.