About Pack Year Calculator

Last updated: October 9, 2026

Pack Year Calculator is a free, independent website that calculates pack-years — the standard measure of lifetime cigarette smoking — and explains what the result means for lung cancer screening in the USA and Germany. It is an information tool, not a medical service.

What the site does — and does not do

It calculates pack-years with the standard formula: (cigarettes per day ÷ 20) × years smoked.
It compares your result with published screening criteria (USPSTF, Medicare/CMS, American Cancer Society, and the German statutory programme).
It does not diagnose anything, does not predict your personal cancer risk, and does not replace a doctor’s assessment. Screening is a decision you make with your doctor.
The site does not currently have a named medical reviewer. Content is written from the primary sources listed below; each page shows the date it was last updated.

Sources we use

Screening criteria: USPSTF 2021, CMS 2022, American Cancer Society 2023, G-BA (Germany) and the LuKrFrühErkV.
Lung cancer risk by pack-years and by years since quitting: Pesch et al., International Journal of Cancer 2012 (SYNERGY).
Life expectancy per cigarette: Shaw et al., BMJ 2000 (about 11 minutes) and Jackson et al., Addiction 2025 (about 20 minutes) — population averages, shown as a range.
Nicotine replacement therapy: Cochrane review, Hartmann-Boyce et al. 2018.
Constituents of cigarette smoke: FDA list of harmful and potentially harmful constituents (111 substances, updated April 2026).

How the site is funded

The site is free and shows no advertising networks. Some pages contain Amazon affiliate links to nicotine replacement products (clearly labelled). As an Amazon Associate I earn from qualifying purchases; the price you pay does not change (affiliate disclosure). Affiliate links do not influence the calculations or the medical information, and the links open a general Amazon search rather than recommending a specific brand.

We receive no money from tobacco companies, screening providers or pharmaceutical companies.

Privacy

All calculations run in your browser; your inputs are not sent anywhere. We set no cookies and use no advertising networks; page-view statistics come from cookieless Cloudflare Web Analytics. Details: Privacy Policy.

Corrections

Guidelines change. If you find an error or outdated information, please email [email protected] with the page and, ideally, a source. We correct errors and update the “Last updated” date on the page.