HSI Calculator (Hepatic Steatosis Index)
Use this tool to estimate your Hepatic Steatosis Index (HSI), a screening score for fatty liver risk. Enter your values below:
Medical note: HSI is a screening aid, not a diagnosis. Always discuss liver concerns with a qualified clinician.
What is the HSI calculator?
The HSI calculator estimates your Hepatic Steatosis Index, a simple clinical score used to screen for possible non-alcoholic fatty liver disease (NAFLD). It combines common lab markers (ALT and AST), body mass index (BMI), sex, and diabetes status into one number.
Because the inputs are usually available from a routine checkup, HSI is often used as a low-cost first step before more advanced tests like ultrasound, FibroScan, or MRI.
HSI formula used in this calculator
This page uses the standard Hepatic Steatosis Index equation:
HSI = 8 × (ALT ÷ AST) + BMI + 2 (if female) + 2 (if diabetes)
- ALT: Alanine aminotransferase
- AST: Aspartate aminotransferase
- BMI: Body mass index in kg/m²
How to interpret your HSI result
Common cutoffs
- HSI < 30: Lower probability of fatty liver
- HSI 30–36: Indeterminate range (gray zone)
- HSI > 36: Higher probability of fatty liver
These cut points are useful for screening, but they do not replace a full medical evaluation. People with liver symptoms, metabolic risk factors, or abnormal labs may still need additional testing even when HSI is below 30.
Why ALT, AST, BMI, sex, and diabetes matter
ALT/AST ratio
The ALT-to-AST relationship can reflect liver cell stress. In metabolic liver disease, ALT often rises earlier than AST in many patients, which influences the HSI score.
BMI and metabolic risk
Excess body fat, especially visceral fat, is strongly linked to fatty liver risk. That is why BMI is directly included in the equation.
Sex and diabetes adjustments
The formula applies a small adjustment for female sex and for diabetes mellitus, both of which shift risk patterns in population studies used to develop HSI.
When to use an HSI calculator
- During preventive health tracking
- After receiving routine liver blood tests
- If you are monitoring metabolic health over time
- As a starting point before discussing results with your doctor
Limitations you should know
No single score can fully evaluate liver health. HSI has practical value, but it also has limits:
- It is a screening index, not a definitive diagnostic test.
- Liver enzymes can fluctuate from illness, medications, exercise, or alcohol use.
- A normal or low score does not always exclude liver disease.
- A high score should prompt follow-up, not self-diagnosis.
How to improve liver health if your score is elevated
1) Focus on sustainable weight loss
Even modest fat loss can improve liver fat content in many people. Gradual progress beats aggressive short-term dieting.
2) Improve insulin sensitivity
Prioritize whole foods, fiber, adequate protein, and consistent movement. Reducing refined sugar and highly processed foods can help metabolic markers over time.
3) Build an activity routine
A mix of aerobic activity and resistance training supports better glucose handling and liver outcomes.
4) Review medications and alcohol intake
Some medications and drinking patterns can affect liver enzymes. Discuss your full history with your care team for tailored advice.
Frequently asked questions
Is HSI the same as a liver ultrasound?
No. HSI is a mathematical estimate. Imaging and specialist tests provide direct information about fat content and fibrosis.
Can I track HSI over time?
Yes. Many people use repeat lab panels and BMI updates to trend HSI. Changes over months can be more informative than a single snapshot.
What if my AST is zero?
AST cannot be zero for this formula because it appears in the denominator (ALT ÷ AST). This calculator requires AST greater than zero.
Bottom line
An HSI calculator is a practical way to estimate fatty liver risk using routine clinical data. It is best used as a conversation starter with your healthcare provider, especially if your result lands in the indeterminate or high-probability range.