Calculate your smoking pack-year history. Used for lung cancer screening eligibility and clinical risk assessment.
A pack-year is a clinical unit used to measure smoking history. It accounts for both how much you smoke and how long you've smoked.
Formula: Pack-years = (cigarettes per day ÷ 20) × number of years smoked.
Examples:
10 cigarettes/day for 20 years = 10 pack-years
20 cigarettes/day for 20 years = 20 pack-years
40 cigarettes/day for 15 years = 30 pack-years
Pack-years are used by doctors to assess cumulative tobacco exposure and guide decisions about lung cancer screening, COPD management, and cardiovascular risk.
The Australian National Lung Cancer Screening Program (NLCSP) uses low-dose CT scanning to detect lung cancer early in high-risk individuals. The eligibility criteria include being aged 50–70, having a smoking history of ≥30 pack-years, and being a current smoker or having quit within the last 10 years.
If you meet these criteria, discuss lung cancer screening with your GP. Early detection of lung cancer significantly improves survival.
No matter how many pack-years you have, quitting smoking at any age provides significant health benefits. Within weeks, your lung function starts to improve. Within a year, your risk of heart disease drops significantly.
Free support: Call Quitline on 13 78 48 or visit quit.org.au for free, personalised support. Talk to your GP about nicotine replacement therapy (NRT), which is available on PBS prescription.
For a full directory of Australian health and crisis helplines, visit AskMyGP helplines directory.
Pack years are the standard way doctors measure cumulative smoking exposure. It matters because your total lifetime exposure — not just whether you currently smoke — determines your risk of lung cancer, COPD, and cardiovascular disease.
You may be eligible for the National Lung Cancer Screening Program (LDCT every 2 years, ages 50–70). Ask your GP. See eligibility criteria →
Increased risk of COPD and emphysema. Your GP may recommend spirometry (lung function testing) to check for early COPD.
The good news: Quitting at any pack-year level reduces your risk. Within 5 years of quitting, stroke risk drops to near non-smoker levels. Within 10-15 years, lung cancer risk drops by 50-70%.