The Importance of Time in Range (TIR)
Time in Range (TIR) shows the percentage of CGM readings within a selected glucose range. For many nonpregnant adults with type 1 or type 2 diabetes, the standard comparison range is 70 to 180 mg/dL. TIR complements A1C by showing how glucose was distributed during the CGM reporting period.
International Clinical Targets
The International Consensus on TIR recommends these goals for Type 1 & Type 2 patients:
- Target Range: > 70%
- Low Range: < 4%
- Very Low: < 1%
- High Range: < 25%
Why TIR adds information beyond A1C
Two people can have the same A1C while their daily glucose patterns differ. One may spend most of the day near the target range; another may have highs and lows that produce a similar average. TIR shows the proportion within range, but variability and time below and above range are still needed to describe the full pattern.
Review TIR with GMI
CGM users can also review Glucose Management Indicator (GMI), a calculated indicator based on mean sensor glucose. Use our GMI Calculator here.
What Counts as In, Below, and Above Range?
A standardized Ambulatory Glucose Profile separates readings into five bands: very low below 54 mg/dL, low from 54 to 69 mg/dL, in range from 70 to 180 mg/dL, high from 181 to 250 mg/dL, and very high above 250 mg/dL. This visualizer combines the two low bands and the two high bands so the three percentages are easier to compare. Use the detailed CGM report when the severity of low or high readings matters.
Consensus targets for many adults with type 1 or type 2 diabetes include more than 70% in the 70–180 mg/dL range, less than 4% below 70 mg/dL, less than 1% below 54 mg/dL, less than 25% above 180 mg/dL, and less than 5% above 250 mg/dL. These are general comparison points—not universal prescriptions. Older adults, people at high risk of hypoglycemia, and people who are pregnant may use different ranges or priorities with their clinicians.
Below range
Review both time below 70 and the more serious time below 54 mg/dL.
In range
For many nonpregnant adults, the comparison band is 70–180 mg/dL.
Above range
Separate time above 180 from time above 250 mg/dL on the full report.
Convert a Percentage Into Hours per Day
Percentages become easier to picture when translated into time. Multiply the percentage by 24 hours. A TIR of 70% is about 16 hours and 48 minutes per day. Four percent below range is about 58 minutes, and 25% above range is 6 hours. These daily equivalents are averages across the report; they do not show whether out-of-range readings occurred in one long episode or several shorter periods.
| Percentage | Approximate time per day | Reporting use |
|---|---|---|
| 1% | 14 minutes | Very low target reference |
| 4% | 58 minutes | Below-range target reference |
| 25% | 6 hours | Above-range target reference |
| 70% | 16 hours 48 minutes | In-range target reference |
| 80% | 19 hours 12 minutes | Progress comparison |
Check the CGM Report Before Comparing TIR
The international consensus recommends reviewing 14 days of CGM data with at least 70% of possible readings active. Less coverage may still be useful, but it makes broad comparisons less dependable—especially when missing time follows a pattern. Check whether the sensor was inactive overnight, during exercise, while traveling, or during another period with different glucose behavior.
Compare like with like. A seven-day report during illness should not automatically be judged against a routine 90-day report. Confirm that both reports use the same target range, time zone, and day boundaries. A change in the percentage can reflect different data coverage as well as a real change in glucose patterns.
How TIR Relates to A1C and GMI
Studies have found a relationship between higher TIR and lower A1C at the population level. A TIR near 70% often aligns roughly with an A1C near 7%, but the relationship has individual variation and should not be used as an exact conversion. TIR is derived from sensor readings; laboratory A1C measures glycated hemoglobin; GMI is calculated from mean CGM glucose. Each describes a different part of glucose management.
When the measures disagree, review the date ranges, sensor coverage, mean glucose, and variability. Laboratory A1C can also be affected by conditions involving red blood cells, hemoglobin, pregnancy, kidney or liver disease, blood loss, or transfusion. The visualizer does not determine why a mismatch occurred.
Look at Patterns, Not Only the Total
An overall TIR can hide a consistent problem at one time of day. The AGP curve and daily traces may show overnight lows, after-breakfast rises, exercise-related changes, or repeated evening highs. Day-versus-night and weekday-versus-weekend comparisons can turn one percentage into a more useful set of questions for a diabetes visit.
Safety comes before chasing a higher TIR number. Reducing time below range may be the first priority for someone with recurrent hypoglycemia, even if the overall TIR temporarily changes. Do not adjust insulin or other medication from this visualizer alone; use current readings and the individualized instructions from the treating clinician.
Time in Range Questions
What is a good Time in Range?
For many nonpregnant adults with type 1 or type 2 diabetes, the consensus comparison goal is more than 70% between 70 and 180 mg/dL. Individual targets may differ.
Does 70% TIR mean 70% of each day?
It is the percentage across the selected report. One day may be higher and another lower, so review daily patterns as well as the combined total.
Can I calculate TIR from finger-stick readings?
Not reliably. Time in Range is designed for frequent CGM readings across day and night. A small set of finger-stick checks cannot measure the percentage of time.
Is the pregnancy target range also 70–180 mg/dL?
No. Pregnancy uses a tighter consensus sensor range, commonly 63–140 mg/dL, and requires individualized obstetric and diabetes care.
Why must the three inputs total 100%?
Every captured reading must be assigned to below, within, or above range. If the values do not total 100%, recheck the CGM report and rounding.
Can TIR replace A1C?
No. TIR adds daily pattern information, while laboratory A1C provides a separate biological measurement. They are commonly reviewed together.
Sources and Further Reading
- Diabetes Care: International Consensus on Time in Range
- CDC: Continuous Glucose Monitors and Time in Range
- Diabetes Care: Standardized CGM and Laboratory Metrics
Reviewed for source alignment on August 15, 2026. This visualizer is educational and does not replace current glucose alerts, a treatment plan, or professional medical advice.