Time in Range: The Number That Matches How You Feel

July 21, 2026 · 3 min read · Reviewed by GlucIQ Clinical Review Workflow

Your A1c is 6.9. Your doctor nods. But you spent half of last week feeling foggy, hungry, and one bad decision from a crash.

Here’s the thing about A1c: it’s an average, and averages can lie. It can’t tell the difference between a steady 140 and a day that swings from 50 to 300.

Time in range can. It’s the percentage of your day spent in the safe zone — 70 to 180. And it matches how you actually feel.

What the experts say

The international experts who set CGM targets recommend: 70% of your day in range, under 4% in the lows, under 5% above 250 (Battelino et al., 2019).

Not 100%. Not perfection. 70% — because the goal is a life you can sustain, not a week of heroic effort.

Why time in range responds to real change

Here’s the encouraging part: this number moves. In the DIAMOND trial, adults who started using a CGM improved their control just from seeing their patterns — no forced changes, just visibility (Beck et al., 2017).

The lesson: you can’t fix what you can’t see. Time in range gives you something to look at that isn’t a 3-month average. It’s a weekly scoreboard.

The two sides of the number

Time in range has two “leaks”: time too high and time too low. Almost everyone’s problem is mostly one of them:

Mostly high: a dosing/timing problem. Basal or bolus math.
Mostly low: a safety problem. And fixing it usually raises your TIR — because lows cause rebound highs.

Look at your 14-day report. Which side is dragging you down? That’s your one thing to work on.

How to move it without burning out

1. Fix the lows first. They’re dangerous, and they steal your range from both sides (the low, then the rebound).

2. Pick one meal. The one that consistently spikes you for hours. Fix that meal’s timing or composition with your team. One meal, done well, beats vague “trying harder.”

3. Watch the overnight window. Nights are where the biggest gains hide. If your nights are unstable, that’s the highest-value conversation you can have.

The one-minute takeaway

A1c tells you where you’ve been. Time in range tells you how your week actually went. Track both — but if you only look at one number this month, make it the one that matches how you feel.

Your Weekly CGM Review: 20 Minutes That Fix Your Whole Week
The Glucose Rollercoaster: Why Your Numbers Bounce (and How to Smooth It)
CGM Data Sharing: Help or Stress for Caregivers?
CGM in Pregnancy: What the Biggest Study Found This is general information, not medical advice. Always check with your care team before changing your insulin.

References

Battelino T, et al. Clinical Targets for CGM Data Interpretation: International Consensus on Time in Range. Diabetes Care. 2019. DOI: 10.2337/dci19-0028
Beck RW, et al. Effect of Continuous Glucose Monitoring on Glycemic Control in Adults With Type 1 Diabetes Using Insulin Injections: The DIAMOND Randomized Clinical Trial. JAMA. 2017. DOI: 10.1001/jama.2016.19975