AST ALT Ratio Calculator

Q: What is a normal AST/ALT ratio?

A normal AST/ALT ratio is usually between 0.7 and 1.0 . In healthy people, ALT is slightly higher than AST, so the ratio stays below 1.0. If your ratio is in this range and both enzyme levels are within normal limits, your liver is likely healthy.

Q: How is the AST/ALT ratio calculated?

The formula is simple: AST ÷ ALT = Ratio . For example, if your AST is 30 U/L and your ALT is 40 U/L, the ratio is 30 ÷ 40 = 0.75 . This calculator does the math for you as soon as you enter your values.

Q: What does an AST/ALT ratio above 2.0 mean?

A ratio of 2.0 or higher is a strong sign of alcoholic liver disease , especially alcoholic hepatitis. Studies show this cutoff has about 90% sensitivity for detecting alcohol-related liver damage. However, it can also appear in Wilson disease or severe cirrhosis. See your doctor for proper testing.

Q: What does an AST/ALT ratio below 1.0 mean?

A ratio below 1.0 means your ALT is higher than your AST . This pattern is common in non-alcoholic fatty liver disease (NAFLD) , viral hepatitis B or C , and drug-induced liver injury. The liver is usually the main source of the elevated enzymes.

Q: Can the AST/ALT ratio tell the difference between alcoholic and non-alcoholic liver disease?

Yes, the ratio helps with this. In non-alcoholic liver disease , the ratio is usually below 1.0 . In alcoholic liver disease , the ratio is typically above 2.0 . However, as non-alcoholic liver disease gets worse and turns into cirrhosis, the ratio can rise above 1.0 too. So the ratio is helpful but not perfect on its own.

Q: Can high AST be caused by something other than liver disease?

Yes. AST is found in the heart, muscles, kidneys, and brain , not just the liver. Heavy exercise, muscle injury, a heart attack, or even some medications can raise AST without any liver damage. That is why doctors look at ALT too, since ALT is more specific to the liver.

Q: What does the inverse ALT/AST ratio mean?

The inverse ratio is just ALT ÷ AST . Some studies and doctors use this version instead. If your AST/ALT ratio is 1.73, the inverse is about 0.58. Both numbers give the same information, just flipped. This calculator shows both for convenience.

Q: Should I fast before getting AST and ALT blood tests?

Fasting is usually not required for AST and ALT tests on their own. However, if your doctor orders a full metabolic panel or lipid panel at the same time, you may need to fast for 8 to 12 hours. Ask your doctor or lab for specific instructions.

Q: What AST/ALT ratio suggests cirrhosis?

A ratio above 1.0 can suggest cirrhosis, regardless of the cause. As liver disease progresses and scarring increases, AST tends to rise more than ALT. A ratio between 1.0 and 2.0 is often seen in patients with advancing fibrosis or early cirrhosis.

AST ALT Ratio Calculator

Updated May 25, 2026 By Jehan Wadia

Enzyme	Male (U/L)	Female (U/L)
AST	10 – 40 (upper limit ~45)	10 – 30 (upper limit ~35)
ALT	10 – 45 (upper limit ~55)	10 – 30 (upper limit ~45)

Enzyme

Male (U/L)

Female (U/L)

AST

10 – 40 (upper limit ~45)

10 – 30 (upper limit ~35)

ALT

10 – 45 (upper limit ~55)

10 – 30 (upper limit ~45)

Introduction

The AST ALT Ratio Calculator divides your AST level by your ALT level to give you a simple number. AST and ALT are enzymes found in your liver. When your liver is hurt or sick, these enzymes leak into your blood. Doctors use the ratio between them to help figure out what might be wrong. A ratio below 1.0 often points to conditions like fatty liver disease or viral hepatitis. A ratio above 2.0 is a strong sign of alcohol-related liver damage. This tool does the math for you instantly, shows where your result falls on a visual scale, and explains what it may mean. Just enter your AST and ALT values from your blood test, and the calculator does the rest.

How to Use Our AST ALT Ratio Calculator

Enter your liver enzyme lab values below and the calculator will show your AST/ALT ratio, what it means, and helpful charts to compare your results.

AST (Aspartate Aminotransferase): Type your AST blood test result in U/L. This number is found on your lab report. It must be between 0.1 and 10,000.

ALT (Alanine Aminotransferase): Type your ALT blood test result in U/L. This number is also found on your lab report. It must be between 0.1 and 10,000.

Biological Sex: Pick Male, Female, or Not Specified. This is optional and only changes the normal reference ranges shown next to your values.

Calculate Button: Click "Calculate" to see your AST/ALT ratio, a color-coded scale, clinical interpretation, bar chart, and reference table that shows where your ratio falls.

What Is the AST/ALT Ratio?

The AST/ALT ratio compares two liver enzymes found in your blood: AST (aspartate aminotransferase) and ALT (alanine aminotransferase). Both enzymes leak into your blood when your liver is damaged. Doctors use this ratio to help figure out what type of liver problem you may have.

Why Does the Ratio Matter?

ALT is found mostly in the liver, while AST is found in the liver, heart, and muscles. When ALT is higher than AST (ratio below 1.0), it usually points to conditions like fatty liver disease or viral hepatitis. When AST is much higher than ALT (ratio of 2.0 or more), it strongly suggests alcoholic liver disease. A ratio between 1.0 and 2.0 can mean the liver has scarring, called fibrosis or cirrhosis. For a broader look at cardiovascular and metabolic health markers, you may also want to check your cholesterol ratio or use our waist to hip ratio calculator to assess related risk factors.

Normal Values for AST and ALT

Normal AST levels are roughly 10–40 U/L for men and 10–30 U/L for women. Normal ALT levels are about 10–45 U/L for men and 10–30 U/L for women. These ranges can vary slightly between labs. Having both enzymes within the normal range is a good sign of liver health. If you're reviewing a full metabolic panel, tools like our GFR calculator can help you assess kidney function alongside your liver results, while an A1C calculator is useful for evaluating blood sugar control, which is closely tied to fatty liver disease risk.

Limitations to Keep in Mind

The AST/ALT ratio is just one clue. It cannot diagnose a condition on its own. AST can rise from heart problems or muscle injury, not just liver disease. If you're monitoring heart health, our heart rate zone calculator, max heart rate calculator, and QTc calculator may also be helpful. Your doctor will look at the ratio alongside your medical history, symptoms, and other test results before making any diagnosis. Maintaining a healthy weight and diet also plays a role in liver health, so you might find our BSA calculator, body fat calculator, or calorie calculator useful as part of an overall wellness assessment.

Frequently asked questions

What is a normal AST/ALT ratio?

A normal AST/ALT ratio is usually between 0.7 and 1.0. In healthy people, ALT is slightly higher than AST, so the ratio stays below 1.0. If your ratio is in this range and both enzyme levels are within normal limits, your liver is likely healthy.

How is the AST/ALT ratio calculated?

The formula is simple: AST ÷ ALT = Ratio. For example, if your AST is 30 U/L and your ALT is 40 U/L, the ratio is 30 ÷ 40 = 0.75. This calculator does the math for you as soon as you enter your values.

What does an AST/ALT ratio above 2.0 mean?

A ratio of 2.0 or higher is a strong sign of alcoholic liver disease, especially alcoholic hepatitis. Studies show this cutoff has about 90% sensitivity for detecting alcohol-related liver damage. However, it can also appear in Wilson disease or severe cirrhosis. See your doctor for proper testing.

What does an AST/ALT ratio below 1.0 mean?

A ratio below 1.0 means your ALT is higher than your AST. This pattern is common in non-alcoholic fatty liver disease (NAFLD), viral hepatitis B or C, and drug-induced liver injury. The liver is usually the main source of the elevated enzymes.

Can the AST/ALT ratio tell the difference between alcoholic and non-alcoholic liver disease?

Yes, the ratio helps with this. In non-alcoholic liver disease, the ratio is usually below 1.0. In alcoholic liver disease, the ratio is typically above 2.0. However, as non-alcoholic liver disease gets worse and turns into cirrhosis, the ratio can rise above 1.0 too. So the ratio is helpful but not perfect on its own.

Why does biological sex affect the reference ranges?

Men naturally have slightly higher AST and ALT levels than women. For example, the upper normal limit for ALT is about 55 U/L for men and 45 U/L for women. Selecting your sex in the calculator shows you the correct normal range so you can see if your values are elevated.

Can high AST be caused by something other than liver disease?

Yes. AST is found in the heart, muscles, kidneys, and brain, not just the liver. Heavy exercise, muscle injury, a heart attack, or even some medications can raise AST without any liver damage. That is why doctors look at ALT too, since ALT is more specific to the liver.

What does the inverse ALT/AST ratio mean?

The inverse ratio is just ALT ÷ AST. Some studies and doctors use this version instead. If your AST/ALT ratio is 1.73, the inverse is about 0.58. Both numbers give the same information, just flipped. This calculator shows both for convenience.

Should I fast before getting AST and ALT blood tests?

Fasting is usually not required for AST and ALT tests on their own. However, if your doctor orders a full metabolic panel or lipid panel at the same time, you may need to fast for 8 to 12 hours. Ask your doctor or lab for specific instructions.

What AST/ALT ratio suggests cirrhosis?

A ratio above 1.0 can suggest cirrhosis, regardless of the cause. As liver disease progresses and scarring increases, AST tends to rise more than ALT. A ratio between 1.0 and 2.0 is often seen in patients with advancing fibrosis or early cirrhosis.

Can medications affect my AST/ALT ratio?

Yes. Some drugs raise ALT more than AST, which lowers the ratio. Others raise AST more. Common examples include acetaminophen (Tylenol), statins, antibiotics, and anti-seizure drugs. Always tell your doctor about all medications and supplements you take before interpreting your results.

How often should I check my AST and ALT levels?

If you are healthy with no risk factors, AST and ALT are checked during routine blood work, usually once a year. If you have liver disease, take medications that affect the liver, or drink alcohol regularly, your doctor may check them every 3 to 6 months or more often.

What if both my AST and ALT are normal but the ratio is high?

If both values are within normal limits, a ratio above 1.0 is usually not a concern. The ratio is most useful when one or both enzyme levels are elevated. For example, an AST of 30 and ALT of 15 gives a ratio of 2.0, but both numbers are normal, so it likely does not indicate disease.

What units does this calculator use?

This calculator uses U/L (units per liter), which is the standard unit for AST and ALT on most lab reports worldwide. If your lab report shows different units, you may need to convert them before entering your values.

Can exercise change my AST and ALT results?

Yes. Intense exercise, especially weight lifting or endurance training, can raise AST levels because AST is found in muscle tissue. ALT can also go up slightly. If you exercised hard in the 24 to 48 hours before your blood test, your results may be temporarily higher than normal.