Time in Range (TIR) is the most important metric that continuous glucose monitors have added to diabetes management — more actionable than A1C alone. Here is what it means and how to use it.
What Is Time in Range?
TIR is the percentage of time your glucose spends within your target range, typically 70-180 mg/dL (3.9-10 mmol/L). Major diabetes organizations now recommend TIR as a primary management target alongside A1C.
TIR Targets (International Consensus)
- Type 1 or Type 2 on insulin: Greater than 70% TIR (70-180 mg/dL)
- Older adults or high-risk patients: Greater than 50% TIR
- Pregnancy with pre-existing diabetes: Greater than 70% TIR with tighter range (63-140 mg/dL)
- Time below range (<70 mg/dL): Less than 4%
- Time below 54 mg/dL: Less than 1%
TIR vs A1C: Why Both Matter
A1C reflects your average glucose over 3 months but reveals nothing about variability. Two people can have identical A1Cs with very different glucose patterns — one stable, one swinging between highs and lows. TIR captures this variability. A1C of 7.0% with 80% TIR is much better than 7.0% with 50% TIR.
How to Read Your TIR Report
Access TIR in your CGM app: Dexcom Clarity, LibreLink reports, or xDrip+ statistics. Look at: total TIR %, time below range (most important to minimize), time above range, and the ambulatory glucose profile (AGP) graph.
Practical Ways to Improve TIR
- Meal timing: Pre-bolusing 15-20 minutes before meals (for insulin users) reduces post-meal spikes
- Carb counting accuracy: Even rough estimates improve TIR when consistent
- Exercise timing: Afternoon exercise tends to improve overnight TIR better than morning exercise for many people
- Sleep glucose: Addressing high or low overnight glucose has a large TIR impact — it is 8 hours of your day
Sharing TIR Data With Your Care Team
Export your Dexcom Clarity or LibreLink report as a PDF for clinic visits. A 14-day or 30-day AGP report gives your provider more actionable data than a single A1C value.