Time in range (TIR) is the proportion of recorded time within defined glucose boundaries. Its meaning depends on those boundaries, the reporting period and the data available. An ambulatory glucose profile (AGP) brings summary metrics and a composite daily profile together.
What the terms count
| Metric | Meaning |
|---|---|
| Time in range | The proportion within the stated lower and upper boundaries. |
| Time below range | The proportion below a stated threshold; reports may separate levels. |
| Time above range | The proportion above a stated threshold; reports may separate levels. |
| Active data | How much of the reporting period has usable recorded readings. |
The 2019 international consensus uses 70–180 mg/dL (3.9–10.0 mmol/L) as a commonly reported range for many adults with diabetes. This reporting convention is not a universal personal target. Pregnancy and other circumstances need different considerations.
A fictional calculation
If a complete 24-hour record contains 18 hours within its defined range, TIR is 18 ÷ 24 = 75%. If data are missing, do not silently count those hours as either in or out of range. Check how the report defines its denominator and active-data percentage. This example does not assess anyone’s health.
How AGP differs from yesterday’s line
An AGP combines data across days into a composite 24-hour profile, often showing a median and percentile bands alongside summary metrics. The composite is not an actual single day, and its shaded bands are not a guaranteed forecast of tomorrow. Inspect daily records when an average hides an unusual event or schedule.
The 2019 consensus recommends approximately 14 days with at least 70% active data for review. Adequate coverage is useful but does not guarantee that a period represents every routine or rare event. Note illness, travel or unusual schedules when discussing a report with a professional.
This is general educational information. Use the instructions for the exact device and discuss personal glucose results or treatment questions with your healthcare professional.
Original sources
- Battelino et al. · International Consensus on Time in Range, 2019
- American Diabetes Association · Diabetes Technology, Standards of Care 2026
Sources reviewed 18 October 2026. Model features and local access should be checked against the current instructions and market record.