What is the TyG index?
TyG stands for triglyceride-glucose. The index combines two routine fasting blood-test results: triglycerides and glucose. Researchers developed it as a low-cost surrogate marker for insulin resistance, especially in settings where a fasting insulin test or a complex research procedure is not practical.
Insulin resistance means tissues such as muscle, liver, and fat do not respond to insulin as effectively as expected. The pancreas may compensate by producing more insulin for a time. Glucose can remain in a laboratory reference range during part of that process, which is one reason researchers study combinations of metabolic measurements instead of relying on a single value.
The TyG index is appealing because fasting triglycerides and glucose are commonly available. That convenience does not turn it into a diagnostic test. The National Institute of Diabetes and Digestive and Kidney Diseases explains that clinicians use established blood tests such as fasting plasma glucose, A1C, and the oral glucose tolerance test to identify prediabetes. TyG is not on that diagnostic list.
A form of fat used to transport and store energy. Levels can respond to recent food, alcohol, glucose control, genetics, illness, and medication.
A snapshot of blood glucose after a fasting period specified by the laboratory or clinician. It is not the same measurement as A1C.
A mathematical transformation written as ln. It compresses a large product into a smaller score. It is not the same as log base 10.
Use it to make a pattern easier to discuss and to compare like with like over time. Do not use it to declare that you do or do not have insulin resistance.
The TyG formula problem most calculators do not explain
There are two TyG calculations in published papers and online tools. They look almost identical when written quickly, but the location of the division by 2 changes the answer substantially.
Example: ln(150 × 100) ÷ 2 = 4.81
Example: ln[(150 × 100) ÷ 2] = 8.92
Both equations start with triglycerides and glucose expressed in mg/dL and both use the natural logarithm. The difference is whether division by 2 happens after the logarithm or inside the logarithm.
The researchers who introduced and validated TyG later published a formula clarification stating that their analyses used the first convention: ln(product) divided by 2. They explained that the formula had been written ambiguously in the original publication. At the same time, a large body of later research uses the inside-log convention and reports scores on the higher scale. That history is why you can see cutoffs near 4.5 in one source and values near 8.5 or 9 in another.
Never compare the two score scales directly
A score of 4.8 from TyG-A and a score of 8.9 from TyG-B can come from the exact same laboratory values. Neither is automatically an error. The question is whether the equation and the comparison source match.
Why this calculator shows both
Hiding one version would make the tool look simpler while leaving you vulnerable to a bad comparison. This calculator labels each convention, shows the substituted equation, and gives you both results without assigning either one a diagnosis or universal risk category.
Metric units are converted before calculation
If your report uses mmol/L, the calculator first converts each measurement to mg/dL. Triglycerides are multiplied by 88.57. Glucose is multiplied by 18.0182. It then applies both TyG formulas to those standardized values.
Unit conversions
Triglycerides: mmol/L × 88.57 = mg/dL
Glucose: mmol/L × 18.0182 = mg/dL
How to use the TyG calculator correctly
- 1
Confirm the sample was fasting
TyG research formulas use fasting triglycerides and fasting glucose. If the sample was not fasting or you are unsure, the calculator will still show the arithmetic but will flag the limitation.
- 2
Choose the units printed on the report
Select mg/dL or mmol/L before entering values. Do not convert the numbers yourself unless you want to verify the calculator.
- 3
Enter triglycerides and glucose from the same draw
Mixing results from different dates can create a number that never existed as a real fasting pattern.
- 4
Keep both original values visible
A changing TyG score does not tell you whether triglycerides changed, glucose changed, or both changed. The components remain clinically meaningful on their own.
- 5
Match the formula before comparing
Use TyG-A only with sources that divide the logarithm by 2. Use TyG-B only with sources that divide the product by 2 inside the logarithm.
Why fasting status matters
Triglycerides can move after eating, and fasting glucose is defined by the conditions of the blood draw. A nonfasting calculation may still be mathematically correct, but it is not the same measurement used to create fasting TyG research thresholds. When fasting status is uncertain, document that uncertainty rather than forcing a label onto the result.
What counts as fasting?
Follow the instructions from the ordering clinician or laboratory. Do not guess based on a generic internet rule, because the requested fasting period and permitted beverages can vary with the ordered tests and your medical situation.
What TyG research actually shows
The first TyG study, published in 2008, compared the index with HOMA-IR in 748 adults and proposed it as a surrogate for identifying insulin resistance in that study population. A 2010 validation study compared TyG with the euglycemic-hyperinsulinemic clamp in 99 participants across a range of body weights and glucose tolerance. The index was inversely correlated with clamp-measured glucose disposal.
Those studies established a reason to investigate TyG. They did not establish a universal online diagnosis. A 2020 systematic review of diagnostic accuracy found moderate-to-low quality evidence and substantial variation among studies. Later research has explored associations with metabolic syndrome, type 2 diabetes, cardiovascular outcomes, fatty liver disease, kidney outcomes, and mortality. Most of that evidence is observational, so it can show association without proving that TyG causes an outcome or that lowering the score itself changes risk.
What the evidence supports
- TyG is inexpensive and uses routine fasting labs.
- It has shown associations with measured insulin resistance in multiple populations.
- It can help researchers sort or compare metabolic patterns.
- Changes can be followed when lab conditions and formula stay consistent.
What the evidence does not support
- A universal diagnostic cutoff for every adult.
- Replacing established diabetes tests or clinical assessment.
- Choosing medication or supplement changes from the score alone.
- Assuming an association proves a treatment effect.
Some papers describe TyG as a biomarker, some call it a surrogate marker, and some use it as a risk predictor. Those terms do not all mean the same thing. On this page, surrogate research marker is the most honest plain-English description.
Is there a normal or high TyG index?
There is no single clinically accepted TyG reference range that applies to every person. Proposed cutoffs vary because studies use different formulas, participants, outcomes, laboratory methods, and statistical goals.
The formula split is the first thing to check. Values near 4 to 5 generally belong to TyG-A, while values near 8 to 10 generally belong to TyG-B. A website that gives a cutoff without printing its exact equation leaves out information you need.
Why study cutoffs vary
- Formula convention: dividing after the logarithm and dividing inside it create different scales.
- Population: age, sex, ethnicity, body composition, and health status differ among cohorts.
- Reference method: studies may compare TyG with HOMA-IR, the clamp, metabolic syndrome, future diabetes, or another outcome.
- Purpose: a research cutoff chosen to catch more possible cases may create more false positives.
- Fasting and laboratory methods: sample conditions and assays can affect both input values.
This calculator therefore reports exact scores and the equation used, but it does not color the result green, yellow, or red. A traffic light would imply a consensus that does not exist.
Higher still means the inputs are higher
Within the same formula and unit convention, a higher TyG score results from a higher product of triglycerides and glucose. That arithmetic fact does not tell you the cause, how much risk belongs to you, or what treatment is appropriate.
TyG compared with A1C, fasting glucose, TG/HDL, and HOMA-IR
Different measurements answer different questions. One should not be used to erase another.
| Measurement | Inputs | Useful context | Key limitation |
|---|---|---|---|
| TyG index | Fasting triglycerides and fasting glucose | Research surrogate for an insulin-resistance-related pattern | Two formula scales and no universal diagnostic cutoff |
| TG/HDL ratio | Triglycerides and HDL cholesterol | Makes a high-triglyceride, low-HDL lipid pattern easier to see | Cannot diagnose insulin resistance and varies across populations |
| Fasting plasma glucose | One fasting glucose measurement | Established screening and diagnostic test when interpreted under clinical criteria | A snapshot that can miss other parts of glucose regulation |
| A1C | Glycated hemoglobin | Reflects average glucose exposure over roughly three months and is an established diabetes test | Can be misleading in some conditions and does not show day-to-day variation |
| HOMA-IR | Fasting glucose and fasting insulin | Common research estimate of insulin resistance | Depends on an insulin assay and does not have one universal clinical cutoff |
| Euglycemic clamp | Controlled glucose and insulin infusion with repeated measurements | Detailed research assessment of insulin sensitivity | Time-intensive, costly, and not a routine self-screening test |
If you want the individual glucose result in longer-term context, use the A1C and Average Glucose Calculator. To explore the lipid pattern separately, use the Triglyceride-to-HDL Ratio Calculator. For a broader cluster of measurements, use the Metabolic Syndrome Criteria Checker.
Worked TyG examples
These examples are hypothetical. They demonstrate the math, not a diagnosis.
| Triglycerides | Fasting glucose | TyG-A: ln(product) ÷ 2 | TyG-B: ln(product ÷ 2) |
|---|---|---|---|
| 100 mg/dL | 100 mg/dL | 4.61 | 8.52 |
| 150 mg/dL | 100 mg/dL | 4.81 | 8.92 |
| 200 mg/dL | 110 mg/dL | 5.00 | 9.31 |
Example 1: 100 and 100
The product is 10,000. The natural logarithm of 10,000 is approximately 9.2103. Dividing that answer by 2 gives TyG-A of 4.61. Dividing the product by 2 first gives 5,000, and the natural logarithm of 5,000 gives TyG-B of 8.52.
Example 2: 150 and 100
The product is 15,000. TyG-A is ln(15,000) divided by 2, or 4.81. TyG-B is ln(7,500), or 8.92. The lab values are identical. Only the formula convention changes.
Example 3: metric input
Triglycerides of 1.7 mmol/L convert to approximately 150.6 mg/dL. Glucose of 5.6 mmol/L converts to approximately 100.9 mg/dL. The calculator uses those converted values, then applies both formulas. It does not multiply the raw mmol/L numbers together.
What can change a TyG result?
A TyG change can come from triglycerides, glucose, or both. The score itself cannot tell you why either input moved.
Short-term conditions
- Fasting versus nonfasting sample
- Recent alcohol intake
- Acute illness or major stress
- Recent food intake
- Laboratory and sampling variation
Longer-term factors
- Glucose regulation and diabetes
- Weight and body composition changes
- Physical activity
- Overall eating pattern
- Liver, kidney, or thyroid conditions
- Genetics and inherited lipid disorders
- Prescription medication and adherence
The National Heart, Lung, and Blood Institute notes that diabetes, thyroid disease, kidney disease, liver disease, weight, alcohol, activity, diet, and some medicines can affect triglycerides. Do not stop or change a prescription or supplement based on a calculated index.
When the index is not the priority
Triglycerides above 500 mg/dL can raise the risk of acute pancreatitis. If your entry is in that range, focus on the triglyceride result itself and contact a qualified healthcare professional promptly. Severe abdominal pain, nausea, or vomiting can require urgent evaluation.
What to do with your TyG result
- 1
Write down the exact formula
Record TyG-A or TyG-B beside the result. A bare number is easy to misread later.
- 2
Keep the source values
Save triglycerides, fasting glucose, units, collection date, and fasting status. Those details matter more than the index alone.
- 3
Review the surrounding pattern
Look at A1C, HDL, LDL, non-HDL cholesterol, blood pressure, waist circumference, medication changes, symptoms, and health history with a clinician.
- 4
Compare under similar conditions
If you track over time, use the same formula and preferably the same fasting conditions. Do not overread small changes that could reflect normal variation.
- 5
Ask a focused question
Try: “Do these fasting triglyceride and glucose results change how you view my overall metabolic risk, and is any follow-up testing appropriate?”
For a structured view across several measurements, add your results to the Metabolic Progress Tracker. If you are trying to understand whether a normal A1C rules out every earlier metabolic change, read Insulin Resistance: Signs, Tests, and What the Numbers Miss.
Why I care about the original numbers
A score should never hide the lab result that created it
In November 2025, my triglycerides were 1,761 mg/dL and my A1C was 7.2%. Eight months later, after prescription medication under physician supervision, diet changes, weight loss, and sustained lifestyle work, my triglycerides were 144 and my A1C was 5.7%. I take metformin and do not use insulin.
No calculated index could have replaced direct medical care when my triglycerides were that high. That experience is why this tool keeps both source values visible, warns when triglycerides need direct attention, and refuses to turn one score into a diagnosis.
Questions and answers
TyG index calculator FAQ
What does TyG stand for?
TyG stands for triglyceride-glucose. The index combines fasting triglycerides and fasting glucose in a logarithmic equation.
What is the correct TyG index formula?
The original authors later clarified that their analyses used ln[fasting triglycerides in mg/dL × fasting glucose in mg/dL] divided by 2. Many later studies use ln[(triglycerides × glucose) divided by 2]. Because both remain common, this calculator shows and labels both results.
Why did another TyG calculator give me a different answer?
First compare the equation. Dividing after the natural logarithm usually produces a value near 4 to 5, while dividing the product by 2 inside the logarithm usually produces a value near 8 to 10. Unit conversion and rounding can also create smaller differences.
What is a normal TyG index?
There is no universal clinical reference range. Published cutoffs depend on the formula, population, outcome, and study method. Do not compare a score with a cutoff unless the equations match exactly.
Can TyG diagnose insulin resistance?
No. It is a surrogate research marker. It may add context, but it does not by itself establish or exclude insulin resistance.
Do I need fasting results?
Yes, if you want a result comparable with the standard TyG research formulas. If the sample was not fasting or you are unsure, the arithmetic can still be shown, but its comparison with fasting research is limited.
Can I use A1C instead of fasting glucose?
No. The standard TyG equation uses fasting glucose, not A1C or estimated average glucose. A1C and fasting glucose describe different aspects of glucose exposure.
Can I use nonfasting triglycerides?
The math will work, but the result is not directly comparable with a fasting TyG formula. Record the sample conditions and ask whether a fasting repeat is appropriate.
Does the calculator work with mmol/L?
Yes. It converts triglycerides to mg/dL using 88.57 and glucose to mg/dL using 18.0182 before applying both equations.
Is a lower TyG score always better?
A lower score within the same formula means the product of triglycerides and glucose is lower. That does not make the index a treatment target or prove that overall health improved. Review the individual values and the larger clinical pattern.
Can medication change TyG?
Medication can affect glucose, triglycerides, or both. Do not start, stop, or change medication because of a calculator result. Review changes with the prescribing clinician.
How often should I calculate TyG?
Use it when you have new fasting laboratory results and a reason to compare the same formula over time. The appropriate schedule for laboratory testing depends on your health, treatment, and clinician's plan.
What if my triglycerides are above 500 mg/dL?
Do not focus on the index. NHLBI notes that triglycerides above 500 mg/dL can raise the risk of acute pancreatitis. Contact a qualified healthcare professional promptly for individualized evaluation.
Are my lab values stored?
No. The calculator runs in your browser. It does not submit, store, or send your entries or calculated results.
Primary and official references
Sources and methodology
The calculator implements both formula conventions exactly as displayed. It uses official sources for fasting glucose and triglyceride context, and peer-reviewed research for the history, validation, and limitations of the TyG index. No universal TyG diagnostic category is assigned.
- Simental-Mendía et al., 2008: The product of fasting glucose and triglycerides as a surrogate for identifying insulin resistance
- Guerrero-Romero et al., 2010: TyG compared with the euglycemic-hyperinsulinemic clamp
- Simental-Mendía and Guerrero-Romero, 2020: The correct formula for the triglycerides and glucose index
- Alizargar et al., 2020: The correct formula to calculate triglyceride-glucose index
- Sánchez-García et al., 2020: Systematic review of TyG diagnostic accuracy
- Araújo et al., 2022: Review of TyG as a cardiovascular biomarker
- Nayak et al., 2024: Systematic review and meta-analysis of TyG diagnostic and prognostic value
- NIDDK: Diabetes tests and diagnosis
- NIDDK: Insulin resistance and prediabetes
- NHLBI: High blood triglycerides
