Pack years for screening and respiratory teams

Why use a calculator for the smoking history?

The FAQs explain that “some smoking histories can be complicated and a calculator simplifies the task and provides a universal standard for smoking load/pack year recording, across all Healthcare settings.” They add that smoking load should be recorded on clinical summaries “so that information can be transferred between clinicians and healthcare systems.”

For COPD, NICE guideline NG115 recommends: “Document an up-to-date smoking history, including pack-years smoked… for everyone with COPD” (recommendation 1.2.2).

How does clinician mode work?

Use the calculator on the clinicians page, or choose A patient on the home page. Clinician mode leaves out the patient explanations.

1. Select every type smoked: cigarettes, cigars, spliffs, cigarillos, bidis, pipe, loose tobacco or waterpipe.
2. For each type, enter the amount and the years, adding a period for each change in amount. Loose tobacco is entered by weight a week, in grams or ounces, and waterpipe as 20-minute sessions a week.
3. Record current or ex-smoker, the date stopped (month optional) and total years smoked. Where the periods give an exact total it is filled in and can be edited; where types may overlap, a range is shown, and overlapping years count once.
4. Show the result: the total and a breakdown by type.

What goes into the record?

The result gives a line to copy into the patient record. For example:

Smoking pack years: 24. Cigarettes 20/day x 15 yrs; cigars 2/day x 5 yrs; loose tobacco 50 g/week x 10 yrs. Current smoker. Years smoked: 25. Ref: A123. Calculated 14/10/2026 at smokingpackyears.com (Masters and Tutt conversion figures, 2010 (bidis added 2024); calculator v2.0).

The optional Your reference field appears on the PDF and the record line. Never enter the patient’s name or NHS number. The PDF can be attached, and the print layout includes the same line. FAQ 8 recommends that people who continue to smoke have their pack years recalculated every five years.

How can patients recall a long history?

FAQ 8 notes that the calculation relies on an accurate history, “which can be determined by asking patients to recall what they smoked in each decade of their life.” See the decade-by-decade method, and changing smoking habits for entering cutting down, restarting and switching tobacco.

Patients can prepare beforehand with the patient guide.

Can we add the calculator to our own website?

Yes. The clinicians page has code to paste into a page on your website, and the calculator resizes itself to fit. The embedded version, at /embed/, sets no cookies, runs no analytics and stores nothing. Add ?mode=clinician to the address to open it in clinician mode.

How do pack years fit into lung screening?

The calculator does not decide who is screened. In a 2023 BMJ letter, Dr Masters wrote that the lung cancer screening programme “will use the codes ex-smoking, smoking, and intensity of smoking to determine those who should be offered screening”, and that these codes “are not numerate but descriptive and are difficult to search.” See lung screening in England and lung screening in the US.