Calculate the AST (SGOT) to ALT (SGPT) ratio or find the missing enzyme value from U/L or IU/L lab results with a unitless output.
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Medical disclaimer: This calculator is for educational purposes only and does not provide medical advice or a diagnosis. AST/ALT results should be interpreted by a licensed clinician in the context of your symptoms, medical history, and other tests. If you have concerning symptoms (such as jaundice, confusion, or severe abdominal pain), seek urgent medical care.
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AST (SGOT) / ALT (SGPT) Ratio Formula
The AST/ALT ratio compares your aspartate aminotransferase level to your alanine aminotransferase level. AST is also called SGOT. ALT is also called SGPT.
- Ratio is the AST/ALT ratio. It has no unit.
- AST is aspartate aminotransferase, also called SGOT. It is usually reported in U/L or IU/L.
- ALT is alanine aminotransferase, also called SGPT. It is usually reported in U/L or IU/L.
To calculate the ratio, enter AST and ALT. The units must match. If your lab report lists both values in U/L or both in IU/L, you can use them directly.
To calculate AST, enter ALT and the ratio. The calculator uses AST = Ratio × ALT.
To calculate ALT, enter AST and the ratio. The calculator uses ALT = AST ÷ Ratio.
U/L and IU/L are commonly used interchangeably for AST and ALT reporting. The ratio cancels the unit, so the result is unitless.
Common AST/ALT Ratio Patterns
Ratio patterns can give context, but they do not diagnose a condition by themselves. Your actual AST level, ALT level, symptoms, medications, alcohol use, and other lab results matter.
| AST/ALT ratio | General pattern | Important note |
|---|---|---|
| Less than 1.0 | ALT is higher than AST | Often seen in many liver enzyme elevations, but it is not specific. |
| About 1.0 | AST and ALT are similar | Interpret with the actual enzyme values and the lab reference range. |
| Greater than 1.0 | AST is higher than ALT | May be seen in several conditions, including non-liver causes of AST elevation. |
| Greater than 2.0 | AST is much higher than ALT | Can be associated with alcohol-related liver injury, but clinical review is needed. |
AST and ALT Unit Notes
| Item | Meaning |
|---|---|
| U/L | Units per liter. Common reporting unit for AST and ALT. |
| IU/L | International units per liter. Often treated the same as U/L for these results. |
| Ratio | Unitless, because AST and ALT are divided using the same unit. |
Example Calculations
Example 1: Calculate the AST/ALT ratio
Your AST is 60 U/L and your ALT is 40 U/L.
The AST/ALT ratio is 1.5.
Example 2: Calculate ALT from AST and ratio
Your AST is 84 U/L and your AST/ALT ratio is 2.1.
The ALT value is 40 U/L.
FAQs
What is a normal AST/ALT ratio?
There is no single normal ratio that applies to every person. A ratio near 1 means AST and ALT are similar. A ratio below 1 means ALT is higher. A ratio above 1 means AST is higher. The ratio should be interpreted with the actual AST and ALT values and your lab’s reference ranges.
Can the AST/ALT ratio diagnose liver disease?
No. The ratio is only one clue. It cannot diagnose liver disease by itself. AST can also rise from muscle injury, heart injury, strenuous exercise, and other causes. ALT is more liver-specific, but it still needs clinical context.
Do AST and ALT need to be in the same unit?
Yes. Use the same unit for both values before calculating the ratio. If both are listed as U/L, enter them as U/L. If both are listed as IU/L, enter them as IU/L. The final ratio has no unit.
