Smoking & life expectancy
Smoking is the single largest preventable cause of early death. A lifelong smoker loses about a decade of life on average — but quitting recovers much of it, and the earlier the better.
Why it matters (the mechanism)
Tobacco smoke damages blood vessels and lung tissue and drives cancer, heart disease and COPD. The harm is dose-dependent and cumulative, but the body begins repairing within weeks of quitting.
The evidence
Heavy smokers lose 10–12 years of life expectancy on average (WHO). Quitting before age 40 removes about 90% of the excess mortality risk (Doll et al., BMJ 2004); even quitting at 60 adds 3+ years.
What to do
- If you smoke, a quit attempt is the highest-impact longevity action available — set a quit date.
- Combine nicotine-replacement or prescribed support with behavioural help; it roughly doubles success.
- Quitting before 40 recovers most of the lost years — but it is never too late to gain some back.
- Avoid second-hand smoke, which carries real cardiovascular risk.
And the chance of reaching 100?
Your odds of reaching 100 rise steeply with your overall forecast. As an illustration, a forecast age of 85 implies roughly a 6.7% chance of reaching 100; a forecast of 92 implies around 21%. Factors like smoking shift where your forecast lands. Get your personal figure in the calculator.
These figures are population-average estimates from peer-reviewed research, applied on top of the official life-table baseline for your country, sex and birth cohort — the US Social Security Administration period life tables, the UK Office for National Statistics, and the WHO Global Health Observatory. They describe statistical tendencies, not personal certainties, and are not medical advice.
Other factors
Frequently Asked Questions
See how smoking and everything else combine in your forecast — plus your chance of reaching 100.
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