This is the strongest single predictor of nicotine dependence. Scoring is weighted heavily — within 5 minutes scores maximum points.
Count all cigarettes smoked on a typical day. Higher daily consumption indicates greater physical tolerance and dependence.
Enter the average price you pay per pack (20 cigarettes). The calculator estimates your daily, weekly, monthly, and annual spend based on your selected cigarette count range.
Select Your Answers Above
Choose your time to first cigarette and daily cigarette count to see your HSI score, dependence level, and personalized cessation recommendations.
How to Use the HSI Calculator
Answer the Two Core Questions
Select how soon after waking you smoke your first cigarette and how many cigarettes you typically smoke per day. Both are categorical choices — pick the option that best describes your usual habit. The calculator scores automatically as you select.
Read Your Score and Dependence Level
Your HSI score (0–6) and extended four-tier dependence classification appear instantly on the right. The color-coded gauge shows exactly where you fall on the dependence spectrum, from Very Low (green) to High (red), with personalized interpretation text for your level.
Explore Cost Impact and Pack-Years (Optional)
Expand the Cost Impact section and enter your pack price to see daily, weekly, and annual spending. Open the Pack-Year Calculator, enter how many years you have smoked, and see whether you meet the USPSTF threshold for annual low-dose CT lung cancer screening.
Use Your Results to Plan Your Quit
Review your cessation recommendations, withdrawal severity prediction, and the health benefit timeline showing what happens to your body after quitting. Export a CSV of your results or print them to share with your doctor or cessation counselor.
Frequently Asked Questions
What is a good HSI score?
A lower HSI score is better — it means less physical nicotine dependence. A score of 0 or 1 is considered Very Low dependence and is associated with the best cessation outcomes, as these smokers typically succeed with behavioral strategies alone and experience only mild withdrawal. A score of 2–3 (Low-Moderate) is common among moderate smokers and indicates you will likely benefit from brief counseling and possibly nicotine replacement therapy. Scores of 4–5 and especially 6 indicate significant physical dependence, where pharmacotherapy is strongly recommended to improve quit success rates. There is no 'bad' score — any score is useful information for planning the right level of support for your quit attempt.
Is the HSI the same as the Fagerstrom Test?
No, but it is closely related. The Fagerstrom Test for Nicotine Dependence (FTND) is a six-question instrument that scores 0–10, covering topics such as difficulty refraining in forbidden places, which cigarette is most difficult to give up, and whether you smoke more in the first hours after waking. The HSI uses only the two strongest predictors from the FTND — time to first cigarette and cigarettes per day — to create a shorter 0–6 scale. Validation research shows the HSI achieves 78% sensitivity and 91% specificity against the FTND, with a kappa agreement of 0.70, making it a clinically effective substitute for rapid screening where administering the full six-question test is not practical.
What does my score mean for my chances of quitting?
Your HSI score is a reliable predictor of the support you will need to quit successfully. Very Low scores (0–1) are associated with high unaided cessation rates — many smokers at this level can quit with willpower and behavioral tools alone. Low-Moderate scores (2–3) indicate a meaningful withdrawal experience, but NRT (patches, gum, or lozenges) reliably doubles quit rates in this group. Moderate-High scores (4–5) strongly predict significant withdrawal symptoms; combination NRT or prescription medications like varenicline can triple abstinence rates compared to unaided quit attempts. At a score of 6, combination pharmacotherapy — such as varenicline plus a nicotine patch — offers the highest success rates and should be discussed with a healthcare provider before attempting to quit.
Should I use nicotine patches if my HSI score is low?
If your score is 0 or 1, nicotine replacement therapy is generally not required and many smokers at this level prefer not to use it. The physical withdrawal will be mild enough that behavioral strategies — setting a quit date, avoiding triggers, and using social support — are usually sufficient. If your score is 2 or 3, optional NRT use is recommended, as it can ease the withdrawal experience and improve your odds. For those with limited smoking habits but who score higher due to a very short time to first cigarette (indicating strong morning drive), light NRT such as a lower-dose patch or gum may still be beneficial. Always discuss with your doctor if you have cardiovascular conditions, as some NRT forms are used cautiously in certain patients.
Can I use this calculator if I smoke fewer than 10 cigarettes a day?
Yes, but be aware of an important limitation. The HSI shows floor effects for very light smokers. A person who smokes 3 cigarettes per day and lights up within five minutes of waking would score 3 — classified as Low-Moderate — even though their absolute consumption is very low. This is because the TTFC question captures powerful morning craving signals that indicate physical dependence regardless of total quantity. Conversely, some intermittent or social smokers who smoke 8 cigarettes per day but only after lunch might score 0–1, reflecting low physical dependence. The HSI is best validated in daily smokers; if you smoke on some days but not every day, a healthcare provider can help you interpret your result in the broader context of your smoking pattern.
How often should I retake the HSI?
The HSI is most useful when taken before a planned quit attempt — it helps you and your care team choose the right cessation support. Consider retaking it after 3 months if you have been actively reducing your cigarette count, as a lower score may confirm that your dependence has decreased and that you might need less pharmacological support for a final quit attempt. If you have relapsed after a quit attempt, retaking the HSI can help assess whether your current smoking pattern has changed. Some research programs use the HSI at baseline and at 6-month follow-up to track changes in dependence across a cessation program. There is no harm in retaking it periodically to monitor your progress.