Pack Year Calculator
Smoking history in pack years.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Pack years
- 16.5
- Total cigarettes
- 120,450
- Screening eligible (US 20+)
- Not by pack years alone
- Packs consumed
- 6,023
Quick answer
One pack year equals smoking 20 cigarettes a day for a year; 20+ pack years usually triggers screening eligibility.
Pack years = (Cigarettes/day ÷ 20) × Years
How to use the Pack Year Calculator
- 1Enter your average cigarettes per day.
- 2Enter total years smoked.
- 3Compare with the 20 pack year screening threshold.
Frequently asked questions
What if my habit varied?
Average across periods, or add pack years for each period separately.
Does quitting reset it?
No, pack years are cumulative, but risk does fall after quitting.