QUICKI Calculator
Enter your fasting insulin and fasting glucose to compute the Quantitative Insulin Sensitivity Check Index (QUICKI). The calculator supports glucose in mg/dL or mmol/L, shows the step-by-step logarithmic math, interprets your result against published reference bands, and explains how QUICKI compares to the HOMA-IR method. Results update instantly as you type.
Formula
Worked example
Fasting insulin 15 uU/mL and fasting glucose 103 mg/dL: log10(15) = 1.1761, log10(103) = 2.0128. Sum = 3.1889. QUICKI = 1 / 3.1889 = 0.3136. This falls in the insulin-resistance range.
What is QUICKI?
The Quantitative Insulin Sensitivity Check Index (QUICKI) is a mathematical index that estimates how sensitive the body is to insulin using just two routine fasting blood values: fasting serum insulin and fasting plasma glucose. It was developed by Katz and colleagues and published in the Journal of Clinical Endocrinology and Metabolism in 2000. Unlike the gold-standard hyperinsulinemic-euglycemic clamp, which requires continuous intravenous glucose and insulin infusions over several hours, QUICKI can be derived from a single blood draw. In the original validation study, QUICKI correlated strongly with clamp-measured glucose uptake (r = 0.78), making it a practical surrogate for clinical and research settings.
How the QUICKI formula works
The formula is QUICKI = 1 divided by the sum of the base-10 logarithms of fasting insulin (in uU/mL) and fasting glucose (in mg/dL). Taking logarithms before summing compresses the wide biological range of these values and makes the index roughly linear with clamp-measured insulin sensitivity - a key advantage over HOMA-IR, which uses the raw product of the two values and is therefore non-linear across the full range. The reciprocal (1 divided by the sum) means that higher insulin or higher glucose - both signs of resistance - produce a smaller QUICKI, while good sensitivity gives a larger number close to or above 0.45. Glucose must be in mg/dL for the standard formula; if your lab reports in mmol/L, multiply by 18.0182 before applying the logarithm. This calculator handles that conversion automatically when you select mmol/L.
Interpreting your QUICKI score
There is no single universally agreed cutoff. The Katz et al. cohort found that 95 percent of healthy non-obese subjects scored above 0.357. A value above 0.45 is generally considered normal sensitivity. Values in the range 0.339-0.45 are associated with progressively increasing resistance and are common in overweight or obese individuals. Below 0.339, risk of obesity-related cardiovascular factors rises sharply; below 0.304, values are typical of established type 2 diabetes in research cohorts. A 2020 study of 5,511 adults set sex-specific metabolic-syndrome cutoffs at 0.343 for men and 0.331 for women. Because population norms and laboratory assays vary, your result should always be interpreted by a clinician who knows your full clinical picture.
QUICKI versus HOMA-IR
HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is the other widely used fasting-only index. It equals fasting insulin times fasting glucose in mmol/L, divided by 22.5. A higher HOMA-IR means more resistance, which is the opposite direction from QUICKI. In validation studies, QUICKI showed a slightly more linear relationship with clamp-measured insulin sensitivity than HOMA-IR, particularly at the extremes of the sensitivity range. Practically, both indices use the same two inputs, so they carry the same information - the choice between them is mostly a matter of convention in a given clinical or research setting. This calculator displays both side by side so you can cross-reference whichever threshold your clinician or protocol uses.
QUICKI reference bands
| QUICKI range | Interpretation | Typical clinical context |
|---|---|---|
| > 0.45 | Normal insulin sensitivity | Healthy non-obese individuals |
| 0.382 - 0.45 | Mildly reduced / borderline | Early metabolic risk; lifestyle modification advised |
| 0.339 - 0.382 | Insulin resistance likely | Obesity, pre-diabetes, metabolic syndrome |
| 0.304 - 0.339 | Significant insulin resistance | Obesity with cardiovascular risk factors |
| < 0.304 | Severe insulin resistance | Type 2 diabetes cohort range in validation studies |
Approximate clinical interpretation ranges derived from Katz et al. (2000) and subsequent validation cohorts. No universal consensus cutoffs have been established; values are population- and lab-specific.
Frequently asked questions
What is a good QUICKI score?
In the original Katz et al. validation study, 95 percent of healthy non-obese individuals scored above 0.357. A value above 0.45 is generally considered to reflect normal insulin sensitivity. Scores between 0.339 and 0.45 suggest mildly to moderately reduced sensitivity, and values below 0.339 are associated with insulin resistance in obesity and metabolic syndrome cohorts. Values below 0.304 have been found in type 2 diabetes research populations.
Does QUICKI replace an HbA1c or oral glucose tolerance test?
No. QUICKI is a screening and research index that estimates insulin sensitivity from fasting labs. It does not diagnose diabetes or pre-diabetes. HbA1c reflects average glucose over roughly three months, and an oral glucose tolerance test assesses how glucose is cleared after a carbohydrate load - both provide information that QUICKI cannot. Your clinician will decide which tests are appropriate based on your symptoms, risk factors and previous results.
What is the difference between QUICKI and HOMA-IR?
Both use the same two fasting values. HOMA-IR multiplies fasting insulin by fasting glucose in mmol/L and divides by 22.5 - a higher number means more resistance. QUICKI takes the reciprocal of the sum of the base-10 logarithms, so a higher number means better sensitivity. QUICKI has a more linear relationship with gold-standard clamp measurements across the full range of sensitivity, but clinically the two indices carry very similar information and are often used interchangeably.
Do I need to fast before getting these blood tests?
Yes. Both fasting insulin and fasting glucose must be measured after at least 8 hours without caloric intake (water is fine). Eating raises both glucose and insulin, which would produce an artificially low QUICKI. Blood should typically be drawn in the morning before breakfast for the most reproducible result.
Can I use mmol/L for glucose?
Yes. This calculator accepts glucose in either mg/dL or mmol/L. Select your preferred unit before entering the value and the tool converts to mg/dL internally (by multiplying by 18.0182) before applying the logarithm, keeping the result consistent with the standard Katz et al. formula.
Why does QUICKI use log10 rather than the raw values?
Fasting insulin in particular spans a very wide biological range and is not normally distributed. Taking the base-10 logarithm of both inputs before adding them compresses that range and linearises the relationship between the resulting index and glucose clamp measurements. This is why QUICKI correlates more linearly with gold-standard insulin sensitivity than the raw product used in HOMA-IR, especially at very low or very high insulin levels.
Sources
- Katz A et al. Quantitative insulin sensitivity check index: a simple, accurate method for assessing insulin sensitivity in humans. J Clin Endocrinol Metab. 2000;85(7):2402-2410.
- Yokoyama H et al. Quantitative insulin sensitivity check index and the reciprocal index of HOMA are useful indexes of insulin resistance in type 2 diabetic patients. Diabetes Care. 2003;26(2):491-492.