Lung Cancer Risk Calculator
Use this lung cancer risk calculator to estimate your chance of a lung cancer diagnosis in the next 6 years if you smoke now or used to smoke.
Updated October 22, 2026
Medical Disclaimer: This calculator gives a general estimate for education only and cannot diagnose a condition. Share your result with your doctor or the clinician who ordered your test, and do not start, stop or change any medicine based on it. Read our full Medical Disclaimer.
How Lung Cancer Risk Is Calculated
Lung cancer risk here means the chance that a person with your answers will be diagnosed with lung cancer within the next 6 years. It comes from the PLCOm2012 model, a risk formula built and tested with the health and smoking records of more than 80,000 people who had smoked.
What Lung Cancer Risk Measures
The result is a probability for a group of people like you, not a test of your own lungs. It cannot find cancer or rule it out. It uses 11 factors: age, education, body mass index (BMI), COPD, past cancer, family history of lung cancer, race or ethnicity, whether you still smoke, how much you smoked, how long you smoked, and how long ago you quit. It covers lung cancer only; our Cancer Risk Calculator looks at lifestyle factors linked to cancer more broadly.
The Formula
Logit = -4.532506 + 0.0778868 x (age - 62) + race or ethnicity value - 0.0812744 x (education level - 4) - 0.0274194 x (BMI - 27) + 0.3553063 x COPD + 0.4589971 x past cancer + 0.587185 x family history + 0.2597431 x current smoker - 1.822606 x (10 / cigarettes per day - 0.4021541613) + 0.0317321 x (years smoked - 27) - 0.0308572 x (years since quitting - 10)
6-year risk = e^logit / (1 + e^logit)
Yes or no answers count as 1 or 0, and education runs from level 1 (did not finish high school) to level 6 (postgraduate degree). The model was published by Tammemägi and colleagues in 2013 using data from the US PLCO (Prostate, Lung, Colorectal and Ovarian) cancer screening trial¹.
How This Calculator Computes Your Result
Enter your details, with height and weight in metric or imperial units. Give your average cigarettes per day, total years smoked and, if you quit, how many years ago. The tool works out your BMI, runs the formula without rounding, and shows your risk as a percent to 2 decimals and as a number out of 1,000 people. It also shows your pack-years and a one-line note on US screening criteria.
What Your Result Means
Your result is compared with 1.51% over 6 years. Researchers proposed this cut-off in 2014 for choosing who to screen². NHS England uses the same cut-off, for people aged 55 to 74, in its Lung Cancer Screening Programme³.
6-year risk | What it means |
Below 1.51% | Below the risk level used to offer screening in research and in England |
1.51% or higher | At or above that risk level |
A risk of 1.51% means about 15 in 1,000 people with the same answers would be diagnosed within 6 years. That threshold is a program line, not a safe or unsafe line for one person.
In the US, screening is based on fixed criteria instead of a risk score. The US Preventive Services Task Force (2021) recommends yearly low-dose CT scans for adults aged 50 to 80 with at least 20 pack-years who smoke now or quit within the past 15 years⁴. The American Cancer Society (2023) uses the same age and pack-year limits but no longer excludes people who quit more than 15 years ago⁶. Our Pack Years Calculator explains those criteria in full.
How Quitting and Smoking Amount Change Your Estimate
The table shows estimates from this model for a 62-year-old White person with some college education, a BMI of 27, no COPD, no past cancer and no family history, who smoked for 30 years.
Status | 10 per day | 20 per day | 30 per day | 40 per day |
Smokes now | 0.70% | 1.72% | 2.31% | 2.68% |
Quit 5 years ago | 0.46% | 1.14% | 1.54% | 1.79% |
Quit 15 years ago | 0.34% | 0.84% | 1.14% | 1.32% |
Each extra year since quitting lowers the odds by about 3%, and still smoking raises them by about 30% compared with having quit¹. Risk climbs fastest between 10 and 20 cigarettes a day, then rises more slowly. Age matters a lot too: with everything else held the same, the model's odds roughly double with every 9 years of age (an odds ratio of 1.081 per year)¹.
How Well the Model Works
Risk scores and fixed rules do not always pick the same people. Selecting the same number of people, PLCOm2012 caught 83.0% of lung cancers, compared with 71.1% for the criteria used in the National Lung Screening Trial¹. A 2014 follow-up found that about 1 in 4 people who met the US criteria of the time had a risk below 1.51%, such as a 55-year-old former smoker with a risk of only 4 in 1,000².
In its validation group the model had an AUC of 0.797¹. AUC is a 0 to 1 score of how well a model ranks people who get the disease above people who do not. In 11,652 smokers in Quebec, Canada, it still ranked people well but predicted only about two thirds of the lung cancers that occurred⁵.
6-Year Lung Cancer Risk by Smoking Amount and Quitting
PLCOm2012 estimates for one example person. Shading shows the 1.51% screening risk level.
- Below 1.51%
- 1.51% or higher
| Status | Cigarettes per day | |||
|---|---|---|---|---|
| 10 | 20 | 30 | 40 | |
| Smokes now | 0.70 | 1.72 | 2.31 | 2.68 |
| Quit 5 years ago | 0.46 | 1.14 | 1.54 | 1.79 |
| Quit 15 years ago | 0.34 | 0.84 | 1.14 | 1.32 |
Use the arrow keys to move between cells.
A Note on Accuracy
This estimate is only as good as your answers, and smoking history is hard to recall exactly. The model was built on US adults aged 55 to 74, so results outside that age range or outside the US are less certain. Race and ethnicity values come from a US study and may not apply elsewhere. It does not use symptoms, scans or other exposures such as radon or asbestos, and it does not apply to people who never smoked or who have had lung cancer.
Frequently Asked Questions
What is considered high risk for lung cancer?
With this model, a 6-year risk of 1.51% or higher is the cut-off NHS England uses to offer screening³. In the US, high risk is defined by age 50 to 80, 20 or more pack-years, and smoking now or quitting within 15 years⁴.
How accurate is a lung cancer risk calculator?
PLCOm2012 ranked people well in its validation group, with an AUC near 0.8¹. It can underestimate or overestimate risk in other populations, so treat the result as an estimate, not a prediction about you⁵.
Does quitting smoking lower your lung cancer risk?
Yes. In this model each year since quitting lowers the odds by about 3%, and former smokers score lower than current smokers with the same history¹.
Should I get screened for lung cancer?
That depends on your age, smoking history and health, and is a decision to make with a doctor. Our Pack Years Calculator checks the US screening criteria, and this tool shows how your risk compares with the 1.51% threshold.
Sources
Selection Criteria for Lung-Cancer Screening, Tammemägi et al., 2013
Evaluation of the Lung Cancer Risks at Which to Screen Ever- and Never-Smokers, Tammemägi et al., 2014
Standard Protocol and Quality Assurance Standards for the Lung Cancer Screening Programme, NHS England, 2025
Lung Cancer Screening Recommendation, US Preventive Services Task Force, 2021
Accuracy of the PLCOm2012 Model in the CARTaGENE Cohort, Jantzen et al., 2023
Screening for Lung Cancer: 2023 Guideline Update From the American Cancer Society, Wolf et al., 2023