TyG Index Calculator
Triglyceride glucose index in mg/dL or mmol/L, with conversion and a research reference.
What it does
The TyG index combines fasting triglycerides and fasting glucose into a single number. It was developed as a low-cost surrogate marker for insulin resistance.
The calculation takes the natural logarithm of the product of triglycerides and glucose, then divides by 2. Both inputs must be in mg/dL for the conventional formula, so the SI version converts mmol/L values before calculating.
Studies have linked higher TyG values with insulin resistance, metabolic syndrome, fatty liver disease, and cardiovascular risk. The index is useful for research and risk stratification, but it is not a stand-alone diagnostic test.
The defaults use triglycerides of 150 mg/dL and fasting glucose of 100 mg/dL. The product is 15,000, its natural log is about 9.6158, and the TyG index is 4.81. The SI defaults of 1.69 mmol/L and 5.55 mmol/L produce the same result after conversion.
How to use
- Choose conventional units in mg/dL or SI units in mmol/L.
- Enter the triglyceride value from the laboratory report.
- Enter the fasting glucose value. A nonfasting value can be used, but it is less comparable.
- Press Calculate to see the TyG index and the converted values used.
- Compare the result with the research reference, not with a diagnostic threshold.
- Interpret the index alongside waist circumference, blood pressure, HDL cholesterol, and clinical history.
Formula
- triglycerides
- Triglycerides in mg/dL. Convert mmol/L by multiplying by 88.57.
- glucose
- Fasting glucose in mg/dL. Convert mmol/L by multiplying by 18.0182.
- ln
- Natural logarithm, base e.
Multiply triglycerides and glucose in mg/dL, take the natural log, then divide by 2. The older printed form ln(TG x glucose / 2) is not equivalent and should not be used. SI conversion factors are 88.57 for triglycerides and 18.0182 for glucose. The 4.68 value is a research reference used in some studies, not a universal clinical cutoff.
Worked example
Example: triglycerides 150 mg/dL and glucose 100 mg/dL
Defaults: triglycerides 150 mg/dL and fasting glucose 100 mg/dL.
- Multiply triglycerides by glucose: 150 x 100 = 15,000.
- Take the natural logarithm: ln(15,000) = 9.6158.
- Divide by 2: 9.6158 / 2 = 4.8079.
- Round to two decimals: TyG = 4.81.
- The result is at or above the 4.68 research reference.
- SI check: 1.69 mmol/L triglycerides is 149.7 mg/dL and 5.55 mmol/L glucose is 100.0 mg/dL, which gives 4.81.
Reference table
| TyG finding | What it means |
|---|---|
| No universal cutoff | TyG is a research and risk marker, not a diagnostic threshold |
| 4.68 or above | Used as a reference cutoff in some insulin resistance studies |
| Below 4.68 | Below that research reference; it does not exclude insulin resistance |
Limits
- TyG is a surrogate marker and does not measure insulin resistance directly.
- Triglycerides change with fasting status, alcohol, diet, and illness.
- Cutoffs vary across studies and populations, and no universal clinical threshold exists.
- The index should not be used alone to diagnose diabetes, metabolic syndrome, or cardiovascular disease.
Common mistakes
- Mixing units, such as triglycerides in mmol/L with glucose in mg/dL.
- Using the incorrect form ln(TG x glucose / 2) instead of ln(TG x glucose) / 2.
- Treating 4.68 as a diagnostic cutoff rather than a research reference.
- Comparing fasting and nonfasting results without noting the difference.
- Ignoring medicines, alcohol, and acute illness that can raise triglycerides.
Try it yourself
Quick checks. Answers sit tucked under each question.
What is TyG for triglycerides 100 mg/dL and glucose 90 mg/dL?
4.55. The product is 9,000, ln(9,000) is 9.10498, and half is 4.5525.
What is TyG for triglycerides 200 mg/dL and glucose 110 mg/dL?
5.00. The product is 22,000, ln(22,000) is 9.9988, and half is 4.9994, which rounds to 5.00.
What is TyG for triglycerides 1.7 mmol/L and glucose 5.0 mmol/L?
4.76. The values convert to 150.6 mg/dL and 90.1 mg/dL, the product is about 13,569, and half of its natural log is 4.7578.
Questions
What does TyG stand for?
Triglyceride glucose index. It combines fasting triglycerides and fasting glucose into a single insulin resistance marker.
Why does the formula use a logarithm?
Triglycerides and glucose are skewed and vary widely. The natural log compresses that spread so the product behaves more evenly across a population.
Is there a normal TyG cutoff?
No universal clinical cutoff exists. Different studies use different values. The 4.68 line is a common research reference, not a diagnostic boundary.
Can I use nonfasting blood work?
You can calculate it, but triglycerides rise after meals and the result is harder to compare with fasting values. Fasting samples are preferred for consistency.
Does a high TyG mean I have diabetes?
No. TyG is associated with insulin resistance and metabolic risk, but diabetes is diagnosed with glucose, HbA1c, or an oral glucose tolerance test.
Why do the SI and mg/dL versions give the same answer?
The tool converts mmol/L to mg/dL before applying the formula. Without conversion, the raw product would be on a different scale and the result would be wrong.
Sources
- Guerrero-Romero et al., TyG index and insulin resistance
- TyG index review in cardiometabolic disease