Smoking Pack-Year Calculator
Calculate smoking pack-years from cigarettes per day and years smoked, and check Korea's national lung cancer screening criteria.
흡연 구간
흡연량이 시기별로 달랐다면 구간을 나눠 입력하세요. 각 구간의 갑년이 합산됩니다.
갑년 = (하루 개비 수 ÷ 20) × 흡연 기간(년)
구간별 갑년
미충족 사유: 30갑년 미만 (현재 20.0갑년)
⚠️ 반드시 확인하세요
- 갑년은 누적 흡연량을 나타내는 임상 지표일 뿐, 질병 진단이나 위험도 확정이 아닙니다.
- 국가폐암검진의 실제 대상자는 국민건강보험공단이 검진 대상 통보로 확정합니다. 이 결과는 기준 충족 여부 참고용입니다.
- 전자담배·궐련형 전자담배는 갑년 산정 기준이 확립되지 않아 일반 궐련 기준으로만 계산됩니다.
- 호흡기 증상(지속 기침, 객혈, 체중 감소 등)이 있다면 갑년과 무관하게 의료기관 진료를 받으세요.
결과 공유
Overview
The smoking pack-year calculator converts cigarettes per day and years of smoking into pack-years, the standard clinical measure of cumulative smoking exposure. If your smoking amount changed over time, you can add multiple periods and the calculator sums them. It also checks whether you meet Korea's national lung cancer screening criteria (age 54–74 with 30+ pack-years), the threshold used to offer biennial low-dose CT screening.
Formula
Pack-years = (cigarettes per day ÷ 20) × years smoked, summed across periods if your intake changed. One pack = 20 cigarettes. Korea's national lung cancer screening criteria: age 54–74 and 30+ pack-years (former smokers who quit 15+ years ago are excluded).
How to Use
- 1Enter your age (used to check the national screening criteria).
- 2Select your smoking status (current or former), and if you quit, enter how many years ago.
- 3Enter cigarettes per day and years smoked. Use 'Add period' if your intake changed over time.
- 4Review your total pack-years and whether you meet the lung cancer screening criteria.
Examples
One pack a day for 20 years
A 55-year-old current smoker who smoked 20 cigarettes (one pack) a day for 20 years.
Two periods with different intake
A 60-year-old who smoked 15 cigarettes a day for 10 years, then 25 a day for 16 years.
Meeting the screening criteria
A 62-year-old current smoker who smoked 30 cigarettes (1.5 packs) a day for 22 years.
Background
A pack-year equals smoking one pack (20 cigarettes) per day for one year, and is the international standard for quantifying smoking history in assessing risk for lung cancer and COPD. In July 2019, Korea became the first country to add lung cancer to its national cancer screening program, offering biennial low-dose chest CT (LDCT) to adults aged 54–74 with a 30+ pack-year history, run by the National Health Insurance Service. The threshold follows the US National Lung Screening Trial (NLST), which showed a 20% reduction in lung cancer mortality with LDCT in smokers aged 55–74 with 30+ pack-years, and Korea's own K-LUCAS pilot study.
Tips
- ✔Think of it as 'packs per day × years': half a pack (10 cigarettes) a day for 20 years is 0.5 × 20 = 10 pack-years.
- ✔If your intake changed over the years, enter separate periods — a rough single-period average can shift the result substantially.
- ✔Even if you meet the pack-year threshold, quitting 15+ years ago excludes you from Korea's national screening — keep track of your quit date.
- ✔Pack-years gauge cumulative exposure, not safety: there is no risk-free level of smoking, and quitting is the most effective prevention at any pack-year count.
FAQ
Q. What exactly is a pack-year?
One pack-year equals smoking 20 cigarettes (one pack) a day for one year. Divide your daily cigarettes by 20 to get packs per day, then multiply by years smoked. For example, 10 cigarettes a day for 30 years is (10÷20)×30 = 15 pack-years. It is the standard unit clinicians use to record smoking history.
Q. Do 30 pack-years automatically qualify me for Korea's lung cancer screening?
The criteria are age 54–74 in the screening year plus a 30+ pack-year history, excluding former smokers who quit 15 or more years ago. Actual recipients are selected by the National Health Insurance Service based on health-checkup questionnaire answers and notified by mail, so meeting the criteria is necessary but the NHIS notice confirms eligibility. Eligible participants pay only about 10% of the LDCT cost.
Q. Do e-cigarettes count toward pack-years?
There is no internationally agreed conversion for vaping or heated tobacco products, since nicotine delivery and usage units differ from conventional cigarettes. This calculator counts conventional cigarettes only; tell your doctor separately about e-cigarette use.
Q. Does a high pack-year count mean I will get lung cancer?
No — pack-years are a statistical risk measure, not a diagnosis. Risk of lung cancer and COPD rises with pack-years, but individual outcomes vary widely, and a low count does not mean zero risk. Persistent cough, coughing up blood, or unexplained weight loss warrants medical attention regardless of pack-years.
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