Fatty Liver Index (FLI) Calculator

Fatty Liver Index (FLI) Calculator for Gastroenterology. Below 30, 30 through below 60, and at least 60 are the original decision bands for ultrasound-defined steatosis. They are not percentages of liver fat, proof of steatohepatitis or a fibrosis assessment.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

FLI uses natural logarithms: x = 0.953 ln(triglycerides in mg/dL) + 0.139 BMI + 0.718 ln(GGT) + 0.053 waist(cm) - 15.745; FLI = 100/(1+exp(-x)). All four inputs must be positive.

When to use this calculator

Use as an estimate of the likelihood of ultrasound-defined hepatic steatosis in an appropriate population. It does not diagnose steatohepatitis, fibrosis, or the cause of fat accumulation.

Inputs used

  • BMI (kg/m2)
  • Waist (cm)
  • Triglycerides (mg/dL)
  • GGT (U/L)

Clinical interpretation

Below 30, 30 through below 60, and at least 60 are the original decision bands for ultrasound-defined steatosis. They are not percentages of liver fat, proof of steatohepatitis or a fibrosis assessment.

Worked example

Fictional teaching case. BMI (kg/m2): 32; Waist (cm): 108; Triglycerides (mg/dL): 220; GGT (U/L): 65. Result: 92.853081 /100. At or above original upper decision limit. FLI estimates the likelihood of ultrasound-detected steatosis in the original setting. It does not diagnose steatohepatitis, fibrosis, etiology or certain absence of liver disease.

Limitations and safety notes

The tool uses fixed labeled units and ignores global display-unit changes, so retained numbers cannot change their meaning. Population and alcohol/metabolic context affect interpretation; this is not a fibrosis score.

Frequently asked questions

Does an FLI of 93 mean 93% liver fat?

No. The index is not a measurement of the percentage of liver tissue containing fat.

What can change the meaning of this result?

The tool uses fixed labeled units and ignores global display-unit changes, so retained numbers cannot change their meaning. Population and alcohol/metabolic context affect interpretation; this is not a fibrosis score.

References

  • Bedogni primary study, equation and original 30/60 decision limits; publisher full text accessed. https://link.springer.com/article/10.1186/1471-230X-6-33

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 9, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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