Average glucose and time in range calculator
Paste your blood sugar readings to see your average, your highest and lowest readings, and the share of readings below, in and above the range you choose. The calculator runs in your browser and nothing you enter is sent anywhere.
What does the calculator show?
- Average, lowest and highest of the readings you entered.
- Time below, in and above range: the share of readings in each band. Read time in range explained.
- Standard deviation and coefficient of variation: how much the readings vary.
- GMI: an estimate of A1c from the average. See GMI explained.
Good to know
The results describe only the readings you typed. A few finger-stick readings are a small sample of a day, so the percentages are a rough picture. A sensor records far more.
Information, not medical advice. Talk to your care team about your own targets and treatment. Never use a converter or a diary entry to work out an insulin or medicine dose.
Sources
- Battelino et al., Diabetes Care, 2019: Clinical targets for continuous glucose monitoring data interpretation
- Bergenstal et al., Diabetes Care, 2018: Glucose Management Indicator (GMI)
Frequently asked questions
Which range does the calculator use?
By default it uses 70 to 180 mg/dL (3.9 to 10.0 mmol/L), the standard range in the international consensus on time in range. You can change both limits.
Is the GMI shown here reliable?
GMI is designed for continuous glucose monitor data covering at least 14 days. For a few finger-stick readings treat it as a rough guide only.
What is the coefficient of variation?
It is the standard deviation divided by the average, as a percentage. It describes how much your readings vary around the average.
Does the calculator save my readings?
No. Everything is calculated in your browser and nothing is stored or sent.
Keep reading
Time in range
Time in range is the share of the day your glucose stays between 70 and 180 mg/dL. How it is calculated and what the international consensus says.
Blood sugar basicsGMI explained
The glucose management indicator (GMI) estimates A1c from the average glucose on a CGM. The formula, a table and why it can differ from your lab A1c.
Daily habits and self-careBlood sugar diary
A practical guide to keeping a blood sugar diary: what to record, why context matters, and a simple template you can copy.