FIB-4 Calculator

Calculate the FIB-4 liver fibrosis index from age, AST, ALT, and platelet count.

941.2K uses Updated · 2026-05-25 Runs locally · zero upload
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How to Use FIB-4 Calculator

  1. Enter age in years.
  2. Enter AST and ALT values in U/L from the same lab panel when possible.
  3. Enter platelet count in 10^9/L. Check the lab unit before typing the number.
  4. Calculate the FIB-4 score and review the low, indeterminate, or high risk band.

Formula & Theory - FIB-4 Calculator

FIB-4 = (age x AST) / (platelet count x sqrt(ALT))
  • Common adult cutoffs are below 1.30 for low risk, 1.30 to 2.67 for indeterminate risk, and above 2.67 for higher risk.

Use Cases for FIB-4 Calculator

  • Reviewing liver fibrosis screening risk from routine blood-test values.
  • Preparing structured information before a hepatology or primary-care appointment.
  • Following changes over time when the same lab units and clinical context are used.

Frequently asked questions about FIB-4 Calculator

What inputs does FIB-4 Calculator need?

Enter age in years.

How should I interpret the result?

FIB-4 is a non-invasive screening index and does not diagnose fibrosis by itself.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.