Estimate how much life expectancy a smoking habit has cost — based on the University College London finding that each cigarette takes about 20 minutes off your lifespan.
What it means
A 2024 paper by researchers at University College London (Sanderson et al., BMJ) re-analyzed long-running cohort data and concluded that each cigarette costs roughly 20 minutes of life expectancy on average — 17 minutes for men and 22 minutes for women. The headline figure is widely cited; the per-sex split reflects the larger relative lifespan loss observed in women smokers.
The 20-minute number is a population-level average derived from observed differences in lifespan between smokers and non-smokers, divided by typical cumulative consumption. Any individual's actual outcome depends on genetics, other risk factors (diet, exercise, alcohol), and whether and when they quit. Treat the number as motivation, not destiny.
Cardiovascular risk drops within months of quitting; lung cancer risk continues falling for a decade or more. Researchers consistently find that quitting at any age extends life — the earlier you stop, the more you reclaim. If you've quit, this calculator only counts the damage done, not the damage avoided.
FAQ
The UCL paper finds women smokers lose more years of life per cigarette smoked than men, even after adjusting for typical consumption levels. The exact biological reasons are still under investigation; possible factors include differences in lung physiology and metabolism of tobacco carcinogens.
It estimates the cost of cigarettes you've already smoked. If you smoked from 18 to 30 and quit, enter 18 and 30. The result is the life cost of those 12 years of smoking. Quitting prevents future damage but doesn't unwind past consumption.
No. The 20 / 17 / 22-minute figures are population averages applied uniformly to every cigarette. The result is best read as a rough scale ("about 3 years" or "about 6 months"), not a precise prediction. The number's value is making the cost feel concrete.
Use your typical or average rate. If you smoked a half-pack daily for the first decade then a pack daily for the second, average it (105 cigarettes per week) for a reasonable estimate. For a precise model, run the calculator twice and add the results.
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