Glucose variability (CV) calculator
Glucose variability is usually given as CV, the coefficient of variation: the standard deviation of your readings divided by their average. The international consensus uses 36% as the line for steady glucose in diabetes; adults without diabetes averaged 17% in one study (Shah et al. 2019).
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How it is worked out
CV (%) = standard deviation ÷ average glucose × 100
Same unit on both, so mg/dL or mmol/L gives the same CV. We use the sample standard deviation (n − 1), as CGM software does. The 36% line is from the international consensus on CGM use (Danne et al. 2017) and was set for people with diabetes.
Sources
- Danne et al. 2017. Diabetes Care 40(12):1631-1640. International consensus on use of continuous glucose monitoring.
- Shah et al. 2019. Journal of Clinical Endocrinology & Metabolism 104(10):4356-4364. CGM profiles in 153 healthy participants without diabetes.
Glucose tools
See it all from your export
The free CGM report reads the whole file: your 24-hour profile (AGP), time in range, GMI, variability, your biggest rises and overnight sensor pressure.
Open the free CGM reportQuestions people ask
- How do I calculate glucose variability (CV)?
- Divide the standard deviation of your readings by their average and multiply by 100. An average of 110 mg/dL with an SD of 22 mg/dL is a CV of 20%. Paste your readings or drop your export above, or type the average and SD your app shows.
- What is a normal glucose CV?
- In a study of healthy adults and children without diabetes, the average CV was 17%, give or take 3 points (Shah et al. 2019). The international consensus uses 36% as the line between steady and unsteady glucose for people with diabetes.
- Why use CV and not just the standard deviation?
- The standard deviation grows with the average: a swing of 30 mg/dL means more around an average of 90 than around 180. CV divides by the average, so people and periods with different averages can be compared.
More free glucose tools
Information, not a diagnosis. HealthOS is a wellness product, not a medical device: these numbers can’t tell you whether anything needs treatment. Talk to a doctor about your results.