Fatty Liver Index (FLI) Calculator
Estimate the likelihood of fatty liver (hepatic steatosis) with the Fatty Liver Index — a simple, non-invasive score from four routine measurements: BMI, waist circumference, triglycerides and GGT. It is widely used to screen for non-alcoholic / metabolic fatty liver disease (NAFLD/MASLD) in the general population, before imaging. Enter the values below; triglycerides can be given in either unit.
How this is calculated
Equation. FLI = (eᴸ ÷ (1 + eᴸ)) × 100, with L = 0.953·ln(TG) + 0.139·BMI + 0.718·ln(GGT) + 0.053·waist − 15.745
| Term | Meaning |
|---|---|
| L | Linear predictor; eᴸ is e raised to the power L |
| TG | Triglycerides in mg/dL (a mmol/L toggle converts via ×88.57); ln is the natural log |
| BMI | Body mass index in kg/m² |
| GGT | Gamma-glutamyl transferase in U/L |
| waist | Waist circumference in cm |
The score runs 0–100: below 30 rules out fatty liver (steatosis unlikely), 30–60 is indeterminate, and 60 or above rules in fatty liver (steatosis likely). Source: Bedogni G et al., BMC Gastroenterology 2006;6:33.
Frequently asked questions
What is the Fatty Liver Index formula?
FLI = (eᴸ / (1 + eᴸ)) × 100, where L = 0.953 × ln(triglycerides) + 0.139 × BMI + 0.718 × ln(GGT) + 0.053 × waist circumference − 15.745. Triglycerides are in mg/dL, BMI in kg/m², GGT in U/L and waist in cm. The result is a probability score from 0 to 100.
What do the FLI results mean?
The Fatty Liver Index uses two cut-offs. Below 30, fatty liver is ruled out (high negative predictive value) — steatosis is unlikely. At 60 or above, fatty liver is ruled in — steatosis is likely and ultrasound or further assessment is reasonable. Between 30 and 60 the result is indeterminate and does not confirm or exclude steatosis.
What triglyceride unit should I use?
The original formula uses mg/dL. If your result is in mmol/L (common outside the US), switch the unit selector and the calculator converts it for you (mmol/L × 88.57 = mg/dL). GGT is reported in U/L (IU/L) almost everywhere, so no conversion is needed.
What is the FLI used for?
The Fatty Liver Index is a first-line, no-cost way to flag likely fatty liver in large populations and everyday practice, using tests that are already routine. A high FLI identifies people who may benefit from ultrasound and metabolic work-up; a low FLI helps reassure and avoid unnecessary imaging. It is also used in research to estimate steatosis prevalence.
Can the FLI diagnose fatty liver on its own?
The FLI cannot diagnose fatty liver by itself. It estimates the probability of steatosis; it does not confirm it, grade its severity, or assess fibrosis (use FIB-4 or the NAFLD Fibrosis Score for that). It can be skewed by anything that raises GGT or triglycerides, such as alcohol or medications. It is a screening tool used alongside imaging and clinical judgement, not a diagnosis. This calculator is an educational reference, not medical advice.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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