Life expectancy calculator
A crude population estimate, not a prediction about you. It ignores genetics, medical history, income, location and chance; all of which matter more than most of the factors above. It is not medical advice.
Average life expectancy in wealthy countries is around 79 for men and 83 for women. Lifestyle factors shift it substantially: heavy smoking removes about a decade, regular exercise adds two years and being very active three, and obesity removes about four. Moderate drinking moves nothing either way.
How to read this estimate
Smoking dominates every other modifiable factor by a wide margin. The adjustment used here, ten years for heavy smoking, is the gap the fifty-year follow-up of British doctors found between smokers and never-smokers, published in the BMJ in 2004, and no combination of the other factors on the panel comes close to offsetting it. The two middle settings are interpolations rather than published figures: four years for a light smoker, one for a former smoker. That single former-smoker step is the crudest thing on the panel, because when someone stopped matters far more than the fact that they did. The same study put the years recovered by quitting at roughly ten for stopping at 30, nine at 40, six at 50 and three at 60, so a former smoker who gave up young sits much closer to a never-smoker than the one-year penalty here suggests. The weight adjustment is drawn from the same kind of evidence: pooled data from 57 prospective studies puts a BMI of 30 to 35 at two to four years of life lost.
Alcohol is the term most likely to surprise anyone who remembers the older figures. Moderate drinking used to be scored as a small gain, on the strength of cohort studies where light drinkers outlived abstainers. That J-shaped curve largely dissolves once the abstainer group is split: it had been mixing lifelong non-drinkers with people who had stopped because they were already ill. Analyses that separate the two find no protective effect, and the WHO position since 2023 is that no level of consumption is established as safe. So moderate drinking neither adds nor removes years on this panel, and heavy drinking removes five.
What the arithmetic cannot include is what varies most between individuals: genetics, existing conditions, income, where you live, and simple chance. Every figure here is a population average with a lifestyle adjustment bolted on, so it describes a large group of people who answered the same way. Read as a personal forecast it is being asked to do something it cannot do.
What people use it for
- Seeing the relative weight of lifestyle factors
- Understanding what smoking costs in years
- Curiosity
- A prompt to talk to a doctor rather than a calculator
Questions
Not very, as a personal prediction. It applies population averages and cannot see your genetics or medical history.
Not smoking, by a wide margin. Nothing else in this list comes close.
The gap is around four years in most wealthy countries and is not fully explained. Both biological and behavioural factors contribute.
Regular activity is consistently associated with a longer life and with better health in those years. This panel credits two years for regular exercise and three at the top of the scale, which is at the cautious end of what the cohort studies report.
No. The studies that appeared to show it were comparing drinkers against an abstainer group that included people who had already stopped for health reasons. Separate those out and the benefit disappears, so the panel scores moderate drinking at zero rather than as a gain.
Act on the direction, not the number. And take health decisions with a doctor, not a web calculator.