How many years do you get back when you quit smoking?
The short answer, the study behind it, and why the real curve is smoother and more honest than the headline numbers suggest.
Written by Lee H. Last reviewed 5 August 2026.
Quit before about 40 and you can expect to recover most of the roughly ten years a lifetime smoker loses on average. Quit later and you still get real years back, just a smaller share of them: the amount recoverable falls steadily with the age you quit, and it falls on a curve rather than dropping in chunks at set birthdays. The rest of this page is that answer worked out in the open, with the source named and the limits stated.
The study's own bands
The benefit of quitting comes from Jha et al., "21st-Century Hazards of Smoking and Benefits of Cessation in the United States," New England Journal of Medicine, 2013, which followed how much of a smoker's excess mortality risk is avoided depending on the age at which they quit. These are the study's own four age bands, not a smooth curve:
| Age at quitting | Years gained (roughly) |
|---|---|
| 25 to 34 | 10 |
| 35 to 44 | 9 |
| 45 to 54 | 6 |
| 55 to 64 | 4 |
A lifetime smoker loses roughly ten years on average, so these four figures amount to roughly all of that loss recovered in the youngest band, then roughly 90%, 60% and 40% in the three that follow. Those are the study's measurements. What a person actually reads off this table depends on treating it as four data points, not as a staircase with hard edges at 35, 45 and 55.
Why it is not a step function
A literal reading of the table above implies that turning 35 costs a smoker ten percentage points of recoverable time overnight. That is not how The Long View's model treats it, and it is not a reasonable way to read the underlying study either. The model interpolates smoothly between the midpoint of each band (ages 29.5, 39.5, 49.5 and 59.5), so the recoverable share moves continuously as age moves, and nobody loses a slice of recoverable time to a birthday landing on the wrong side of a line.
A concrete case makes the difference visible. Age 40 sits just past the midpoint of the 35 to 44 band, so interpolation toward the next band, 45 to 54, has already started by the time someone turns 40. The model gives a 40-year-old a recoverable share of 88.5%, not the clean 90% a naive reading of the headline band would suggest. The full arithmetic behind that figure, including a worked example at age 40, is on the methodology page.
Recovery is front loaded
Knowing the recoverable share only answers how much can eventually come back, not how quickly. None of it lands the day someone quits. The model returns that recoverable time on a curve that is fast at first and slows afterward: roughly half of it returns within about the first three years smoke-free, and the curve keeps rising after that rather than stopping. That shape is anchored to real cessation milestones, coronary risk roughly halved within a year of quitting, stroke risk approaching a never-smoker's within about five years, and coronary risk converging with a never-smoker's by about fifteen. The single mathematical curve used to connect those milestones is a modelling choice made for a clear estimate, not a number published in any one study.
The honest ceiling
There is a ceiling on all of this, and it falls directly out of how the model is built rather than being a caveat added afterward. Quitting moves the forecast back toward the average life expectancy for someone of that age and sex. It cannot move it past that average. However early someone quits and however long they stay quit, the forecast can approach the baseline and never exceed it.
What this cannot tell you
Two limits, stated plainly:
- The baseline is not a never-smoker figure. It comes from a general-population life table, which includes smokers, because that is the closest well-documented public figure available. The true never-smoker baseline would be somewhat higher, so if this estimate is wrong, it is wrong in the direction of understating what quitting is worth.
- Anything past age 64 is extrapolation, not a finding. Jha et al.'s published bands stop at 64. Beyond that age the model continues the same slope and floors it, which is a reasonable way to extend an unfinished curve, but it was not measured by the study and this page will not present it as if it were.
Everything on this page is a motivational estimate built from population averages. It is not a prediction about you, it does not diagnose, treat or prevent any condition, and it is not medical advice. Talk to a doctor or a quitline about stopping smoking. In the US, that is 1-800-QUIT-NOW.
Sources
- Jha, P. et al., "21st-Century Hazards of Smoking and Benefits of Cessation in the United States", New England Journal of Medicine, 2013.
- US Social Security Administration, 2023 period life table, Social Security area population.
See this shape for your own age on the life expectancy calculator. The full arithmetic behind every number on this page, including how the loss side of the equation works, is on the methodology page. Back to all guides.