Question 1

What does HOMA-IR measure?

Accepted Answer

HOMA-IR estimates fasting insulin resistance from glucose and insulin. It is a surrogate index derived from a model, rather than a direct measurement of tissue glucose uptake.

Question 2

How is HOMA-IR calculated?

Accepted Answer

Multiply fasting glucose in mg/dL by fasting insulin in µIU/mL and divide by 405. With glucose in mmol/L, divide the product by 22.5.

Question 3

What is a normal HOMA-IR level?

Accepted Answer

There is no universal normal cutoff. Assays and study populations differ; use an appropriate laboratory or research reference with clinical interpretation.

Question 4

What is the difference between HOMA1 and HOMA2?

Accepted Answer

HOMA1 uses simple approximation equations. HOMA2 uses an iterative computer model; its results cannot be reproduced by relabelling the HOMA1 equations.

Question 5

Does this website calculate HOMA2-IR?

Accepted Answer

No. EndoCalc calculates HOMA1. For HOMA2, use Oxford’s official software and follow its licensing and input requirements.

Question 6

Can I calculate HOMA-IR with C-peptide?

Accepted Answer

C-peptide cannot replace insulin in the HOMA1 equation. Oxford’s HOMA2 software supports C-peptide within its own model and documented conditions.

Question 7

Does HOMA-%B show how many beta cells I have left?

Accepted Answer

No. HOMA-%B estimates basal beta-cell function relative to a reference. It does not count cells or directly measure beta-cell mass.

Question 8

Why is HOMA-%B unavailable at low glucose?

Accepted Answer

The HOMA1-%B denominator is glucose minus 3.5 mmol/L. At or below that value the approximation is unsuitable, and near it small changes produce large results.

Question 9

Can reciprocal HOMA sensitivity exceed 100%?

Accepted Answer

Yes. The reciprocal index is 100 divided by HOMA1-IR. Values above 100% are mathematical reference values, not the percentage of a maximum biological response.

Question 10

Do I need to fast for HOMA-IR?

Accepted Answer

HOMA uses paired fasting measurements. Follow your clinician’s and laboratory’s instructions; fasting glucose tests commonly require at least eight hours without food, with water allowed.

Question 11

Can I use a glucose reading taken after a meal?

Accepted Answer

A post-meal value does not meet the fasting steady-state assumptions of HOMA. Use paired fasting laboratory glucose and insulin for the original calculation.

Question 12

Can insulin and glucose come from different days?

Accepted Answer

Use paired measurements from the same fasting sample. Combining different sampling conditions can distort the relationship that the HOMA model assumes.

Question 13

Can I use HOMA while taking insulin?

Accepted Answer

Injected insulin and treatment effects complicate interpretation. Do not use the fasting insulin-based calculators here during insulin treatment; discuss assessment with your clinician.

Question 14

Are serum and plasma insulin interchangeable?

Accepted Answer

Not necessarily. Oxford describes plasma-based inputs and notes that using serum insulin requires attention to assay differences and may need to be reported as a limitation.

Question 15

Does a high HOMA-IR diagnose diabetes?

Accepted Answer

No. Diabetes assessment uses established glucose and A1C tests, sometimes with repeat confirmation. HOMA-IR alone is not a diagnostic criterion.

Question 16

Can insulin resistance occur with normal blood glucose?

Accepted Answer

Yes. The pancreas can produce more insulin to help keep glucose within range. Normal glucose alone does not directly measure insulin sensitivity.

Question 17

What are the symptoms of insulin resistance?

Accepted Answer

Insulin resistance and prediabetes often cause no symptoms. Risk factors and appropriate laboratory testing are more informative than symptoms alone.

Question 18

Can insulin resistance improve?

Accepted Answer

Physical activity and weight management, where appropriate, can help reduce risk. Agree on an individual plan with your health care team rather than treating a calculator score.

Question 19

Is insulin resistance associated with PCOS?

Accepted Answer

PCOS is associated with a higher likelihood of insulin resistance. A HOMA result alone does not diagnose PCOS or determine its treatment.

Question 20

Which logarithm does QUICKI use?

Accepted Answer

QUICKI uses base-10 logarithms of insulin in µIU/mL and glucose in mg/dL. Entering glucose in mmol/L directly into the formula gives a different result.

Question 21

Is a higher QUICKI value better?

Accepted Answer

Higher QUICKI generally indicates greater insulin sensitivity. It is a research surrogate; clinical interpretation depends on the context and population.

Question 22

Can I calculate an insulin resistance index without insulin?

Accepted Answer

TyG uses fasting triglycerides and glucose without an insulin measurement. It is a different surrogate and should not be treated as interchangeable with HOMA.

Question 23

Does the TyG index use a natural logarithm?

Accepted Answer

This calculator uses ln[(triglycerides × glucose)/2], with both concentrations in mg/dL. The division by two is inside the logarithm.

Question 24

What is a normal TyG index?

Accepted Answer

Interpretation depends on the study population and equation convention. Check the exact formula before comparing values with a published threshold.

Question 25

What average glucose corresponds to HbA1c of 7%?

Accepted Answer

The ADAG equation gives approximately 154 mg/dL, or 8.6 mmol/L. This is a population-based estimate rather than an exact prediction for every person.

Question 26

Do I need to fast for an HbA1c test?

Accepted Answer

An HbA1c test itself does not require fasting. If other blood tests are ordered at the same visit, follow the preparation instructions for those tests.

Question 27

Can I estimate HbA1c from one fasting glucose result?

Accepted Answer

No reliable individual estimate follows from a single fasting reading. The reverse ADAG equation expects representative average glucose over time.

Question 28

Why can HbA1c and average glucose disagree?

Accepted Answer

A1c reflects glucose exposure over time, while individual readings capture moments. Changes in red blood cells, some hemoglobin variants, and other conditions can also affect A1c accuracy.

Question 29

Are mmol/L and mmol/mol the same?

Accepted Answer

No. Blood glucose commonly uses mmol/L. HbA1c uses mmol/mol in IFCC reporting. They describe different quantities and require different conversions.

Question 30

Why do insulin converters use 6.0 or 6.945?

Accepted Answer

Different reporting conventions use different conversion factors. This site makes the factor explicit and defaults to the 6.945 factor in the linked Mayo catalog; check your laboratory.

Question 31

Can C-peptide be converted to insulin?

Accepted Answer

Not by a fixed concentration multiplier. Their handling and clearance differ, so a C-peptide unit conversion cannot produce an insulin concentration.

Question 32

Are my calculator values saved?

Accepted Answer

EndoCalc performs calculations in your browser. The application does not save inputs or send them to an analytics service. Copying or printing a result creates a record you control.

Question 33

How do I calculate adult BMI?

Accepted Answer

Divide weight in kilograms by height in meters squared. For example, 70 kg and 1.75 m give BMI 22.86 kg/m².

Question 34

Does BMI measure body fat or insulin resistance?

Accepted Answer

BMI relates weight to height. It does not directly measure body fat or insulin sensitivity and should be considered alongside other health information.

Question 35

Can children use this BMI calculator?

Accepted Answer

This tool is for adults age 20 and older. Children and teens need an age- and sex-specific BMI assessment rather than adult interpretation.

Question 36

Where should I measure my waist?

Accepted Answer

Place a level tape midway between the lowest ribs and the top of the hip bones. Read the measurement after breathing out normally.

Question 37

Can I use inches for waist-to-height ratio?

Accepted Answer

Yes. Both lengths must use the same unit in the equation. This calculator converts each input to centimeters before dividing waist by height.

Question 38

Is waist-to-height ratio a body-fat percentage?

Accepted Answer

No. A ratio of 0.5 means waist circumference is half the height; it does not mean 50% body fat.

Question 39

Is a fasting insulin test the same as an HbA1c test?

Accepted Answer

No. Insulin testing measures the hormone in a blood sample; HbA1c reflects glucose exposure over time. They answer different questions.

Question 40

Should I stop medication before a fasting insulin test?

Accepted Answer

Ask the ordering clinician about medicines and supplements. Do not stop prescribed medication on your own to obtain a calculator result.

Question 41

Can I drink water before a fasting blood test?

Accepted Answer

Plain water is generally allowed during a blood-test fast. Follow the specific instructions provided for your ordered tests.

Question 42

Can I drink coffee during a blood-test fast?

Accepted Answer

General fasting guidance allows plain water and excludes other drinks, including coffee. If you consumed something else, tell the laboratory before the sample is collected.

Question 43

What if I accidentally eat before the test?

Accepted Answer

Tell the laboratory or clinician before the blood draw. They can decide whether to proceed or reschedule; do not label a nonfasting sample as fasting.

Question 44

Does HbA1c show today’s glucose level?

Accepted Answer

HbA1c reflects glucose exposure over approximately three months. It cannot show the timing or size of a particular glucose spike.

Question 45

Why might HOMA results differ between tests?

Accepted Answer

Fasting conditions, biological variation, and assay differences can change results. Use comparable sampling conditions and discuss meaningful changes with a clinician.

Your questions, in context.