# Heaviness of Smoking Index Calculator (HSI)

URL: https://speedycalculator.com/calculators/health/hsi/
Last updated: 2026-10-30

> The heaviness of smoking index calculator uses just two questions – time to first cigarette after waking and cigarettes per day – to estimate nicotine dependence on a 0–6 scale.

## Inputs

- How soon after waking do you smoke your first cigarette?
- How many cigarettes a day do you smoke?

## Results

- Heaviness of smoking index
- Dependence

## Formula

```
Score = sum of the points for each item
```

## Explanation

The HSI uses the two most predictive items of the Fagerström test and performs almost as well as the full test, so it is popular in busy clinics and surveys.

### How to use the Heaviness of Smoking Index Calculator

- **How soon after waking do you smoke your first cigarette?**
- **How many cigarettes a day do you smoke?**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation.

### Scoring table

ItemAnswers and pointsHow soon after waking do you smoke your first cigarette?Within 5 minutes = 3; 6–30 minutes = 2; 31–60 minutes = 1; After 60 minutes = 0How many cigarettes a day do you smoke?10 or fewer = 0; 11–20 = 1; 21–30 = 2; 31 or more = 3

### Inputs explained

FieldWhat to enterHow soon after waking do you smoke your first cigarette?Choose one: Within 5 minutes, 6–30 minutes, 31–60 minutes, After 60 minutesHow many cigarettes a day do you smoke?Choose one: 10 or fewer, 11–20, 21–30, 31 or more
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — How soon after waking do you smoke your first cigarette?: 6–30 minutes; How many cigarettes a day do you smoke?: 11–20.

Results — **Heaviness of smoking index = 3 / 6**; Dependence = Moderate.

## Key terms

- **HSI**: Heaviness of Smoking Index.

## FAQ

**What is a high HSI?**
5 or 6.

**Why is time to first cigarette so important?**
Smoking soon after waking is a strong sign of physical dependence.

**How is HSI used?**
To decide the strength of nicotine replacement therapy.


## Sources

- [Heatherton TF et al. Measuring the heaviness of smoking. Br J Addict, 1989](https://pubmed.ncbi.nlm.nih.gov/2790006/)