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Liver Enzyme (ALT/AST) Calculator

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Enter your ALT and AST results to check each value and your AST/ALT ratio.

Liver Enzyme (ALT/AST) Calculator

Live
ALTNormal
ASTNormal
AST/ALT ratio0.83 (Low)
This is informational only, not a diagnosis. The ratio is most meaningful when at least one enzyme is elevated - discuss results with a doctor.

The reference ranges

ALT: Men 7-56 U/L Normal, Women 7-45 U/L Normal AST: 10-40 U/L Normal (both sexes) AST/ALT ratio = AST / ALT Under 1.0: Low (NAFLD/viral hepatitis pattern) 1.0 to 2.0: Intermediate Over 2.0: High (alcohol-related liver disease pattern)
Example

ALT 30 U/L, AST 25 U/L: ratio = 25/30 = 0.83, in the Low range - the most common pattern, typically seen in non-alcoholic fatty liver disease or viral hepatitis when enzymes are elevated, or simply a normal healthy ratio when both values are in range, as here.

Step-by-step guide

  1. Get a liver function panel from a blood test - ALT and AST are standard components, often alongside ALP and bilirubin.
  2. Enter both values in U/L along with your sex, since the ALT range differs between men and women.
  3. Review each value plus the AST/ALT ratio - the ratio helps narrow down the likely pattern of liver enzyme elevation, but is most informative when at least one value is actually elevated.

Why the ratio helps distinguish causes

ALT is found mostly in the liver, making it a fairly specific marker for liver cell injury. AST is found in the liver too, but also in the heart, muscles, kidneys, and other tissues, so it's less liver-specific on its own. Comparing the two gives more information than either alone: a ratio under 1 (ALT higher than AST) is the most common pattern in fatty liver disease and viral hepatitis, while a ratio over 2 (AST much higher than ALT) is a classic signature of alcohol-related liver damage. The ratio isn't meaningful, though, when both enzymes are comfortably within their normal ranges.

Common mistakes

Over-interpreting the AST/ALT ratio when both values are normal - the ratio is a pattern-recognition tool for abnormal results, and doesn't carry the same meaning when neither enzyme is actually elevated.
Attributing any mild elevation to serious liver disease - a mildly elevated ALT or AST is common and often caused by recent intense exercise, certain medications, or supplements, not necessarily liver disease.

Frequently asked questions

What does an AST/ALT ratio above 2 usually mean?

It's a classic pattern associated with alcohol-related liver disease, though it can also appear with muscle injury or advanced cirrhosis. The pattern is more meaningful when at least one of the enzymes is also elevated.

Is a ratio under 1 always concerning?

No - it's actually the most common pattern, both in healthy individuals with normal enzyme levels and in conditions like fatty liver disease or viral hepatitis when levels are elevated. Context and the absolute values matter more than the ratio alone.

Why is AST less liver-specific than ALT?

ALT is found predominantly in the liver, while AST is also present in the heart, skeletal muscle, kidneys, and other tissues - so an elevated AST could reflect injury to any of those organs, not just the liver.

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