Time in range (TIR)
Also called time in target range.
Time in range is the share of CGM values, and of the day, that falls between 70 and 180 mg/dL (3.9 to 10.0 mmol/L). The 2019 international consensus made it one of the core CGM metrics, next to time below range and time above range. It is read over 14 days, with the sensor active at least 70% of that time. (International consensus on time in range, 2019)
Target
More than 70% of the time at 70–180 mg/dL (3.9–10.0 mmol/L) for most adults with type 1 or type 2 diabetes; more than 50% for older or high-risk adults. (ADA Standards of Care 2026, section 6; International consensus on time in range, 2019)
Formula
TIR (%) = CGM values from 70 to 180 mg/dL ÷ all CGM values × 100
Worked example
A CGM that records every 5 minutes stores about 4,032 values in 14 days. If 2,903 of them sit between 70 and 180 mg/dL, TIR is 72%, or about 17 hours 17 minutes a day. The consensus paper links each 10% gain in TIR to an A1C about 0.5% lower.
Related terms
- Time below range
- Time above range
- Time in tight range
- Glucose management indicator
- A1C
- Ambulatory Glucose Profile report
Sources, quoted
- International consensus on time in range, 2019: “Time in range (TIR): % of readings and time 70–180 mg/dL (3.9–10.0 mmol/L) In range”
- International consensus on time in range, 2019: “The metric includes three key CGM measurements: percentage of readings and time per day within target glucose range (TIR), time below target glucose range (TBR), and time above target glucose range (TAR)”
- International consensus on time in range, 2019: “Percentage of time CGM is active (recommend 70% of data from 14 days)”
- ADA Standards of Care 2026, section 6: “A goal time in range of >70% in people using CGM is appropriate for many nonpregnant adults.”
- International consensus on time in range, 2019: “Therefore, we have lowered the TIR target from >70% to >50% and reduced TBR to <1% at <70 mg/dL (<3.9 mmol/L) to place greater emphasis on reducing hypoglycemia with less emphasis on maintaining target glucose levels”
- International consensus on time in range, 2019: “An increase in TIR of 10% (2.4 h per day) corresponded to a decrease in A1C of approximately 0.5% (5.0 mmol/mol)”
Every quote above is checked against its source page before each update of this site; last checked 2026-10-06. The worked example is our own arithmetic. This page explains a term; it is not advice for a person's treatment.