Pack-year calculator and lung screening check

Multiply the number of packs smoked per day by the number of years smoked. If you count cigarettes, divide cigarettes per day by 20 first. For example, 30 cigarettes a day for 20 years is 1.5 × 20 = 30 pack-years.

Twenty pack-years is the smoking history at which USPSTF, Medicare, and the American Cancer Society recommend yearly lung cancer screening for adults 50 and older. It equals one pack a day for 20 years, or two packs a day for 10 years.

Under USPSTF and Medicare criteria, screening stops once it has been more than 15 years since quitting. The American Cancer Society's 2023 guideline removed that limit, so it recommends screening for former smokers with 20+ pack-years regardless of when they quit. Insurance coverage may follow USPSTF, so ask your clinician and your plan.

Medicare Part B covers a yearly low-dose CT scan for people aged 50 to 77 with no symptoms, a smoking history of at least 20 pack-years, who currently smoke or quit within the last 15 years, and who have an order from a clinician. A counseling and shared decision-making visit is required before the first scan. If you qualify, you typically pay nothing for the scan when the provider accepts assignment.

A low-dose CT (LDCT) scan uses a small amount of radiation to take detailed pictures of the lungs. It takes only a few minutes, needs no needles, and is the only recommended test for lung cancer screening.

Screening guidelines use cigarette pack-years, so cigars, pipes, and e-cigarettes are not part of the calculation. They can still affect lung health, so mention them to your clinician.

It depends on your risk. In the National Lung Screening Trial, yearly low-dose CT lowered lung cancer deaths by 20% among people with a heavy smoking history. People at higher risk gain the most, while everyone screened faces some chance of false alarms and follow-up tests. The benefits and harms section above shows the numbers for people with your risk.

PLCOm2012 is a published lung cancer risk model (Tammemägi et al., New England Journal of Medicine, 2013). It estimates the chance of being diagnosed with lung cancer in the next 6 years using age, education, BMI, COPD, personal and family cancer history, race or ethnicity, and smoking intensity, duration, and years since quitting. Screening programs in England and Ontario, Canada use it to decide who to invite, with thresholds such as 1.51% or 2% over 6 years. It was developed in adults aged 55 to 74, so estimates outside that range are less certain.

Yes. Medicare requires a counseling and shared decision-making visit, using one or more decision aids, before a patient’s first screening scan. In the clinician view, this calculator checks eligibility, shows personalized benefits and harms, prints a one-page decision aid in English, Spanish, or Chinese, and adds a checklist of the required elements to the chart note. Clinicians remain responsible for the visit and its documentation.

For Medicare, the visit is HCPCS G0296 and the screening scan is CPT 71271, with no coinsurance or deductible. In a physician office it can be billed the same day as another visit with modifier 25. In an FQHC or RHC it is a standalone visit, but it is not paid separately if billed the same day as another visit there. It can be done by telehealth (modifier 95, or 93 for audio-only), and Medicare’s home and audio-only flexibilities run through December 31, 2027. Medicaid coverage and rules vary by state, and private plans cover the scan without cost sharing but may handle the counseling visit differently. Claims need a smoking diagnosis code (Z87.891 or F17.21x). Information as of October 2026; verify with your Medicare contractor or payer.

No. Everything is calculated in your browser. Nothing you type is stored or sent to Oatmeal Health or anyone else.

Call 1-800-QUIT-NOW (1-800-784-8669) for free support in every U.S. state, or visit smokefree.gov. Quitting at any age lowers your risk.