What is a normal time in range without diabetes?
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Far above the 70% printed on your sensor report, which is a goal for adults with diabetes, measured on a wider range of 70 to 180 mg/dL. Healthy people spent 87 to 96% of the day between 70 and 140 in the two biggest studies. Compare your own days with each other instead of chasing a score.
What we’d do
Check which range your report uses before you trust the percent. If it’s 70 to 180, expect to be in the high 90s and don’t celebrate 75%. If it’s 70 to 140, anywhere from the high 80s to the mid 90s looks like the healthy groups. Then use the number to compare your weeks with each other.
Why the 70% confuses people
Time in range came from diabetes care. In 2019, an international panel set the targets you see on sensor reports. For most adults with type 1 or type 2 diabetes, the goal is more than 70% of the day between 70 and 180 mg/dL, which is about 16 hours and 48 minutes. The panel said these targets should be personalized for each person with diabetes.
A healthy person who sees “time in range 92%, goal 70%” thinks they’re crushing it, and someone who sees 75% thinks they’re fine. Neither number means what they think, because the goal was built for people with diabetes. Comparing yourself with it is like grading yourself on a curve made for a different class.
What healthy people do
| Group | Who | Time from 70 to 140 | Time above 140 |
|---|---|---|---|
| Shah 2019 | 153 healthy, non-obese people aged 7 to 80 | 96% | about 30 minutes a day |
| Framingham 2025, normal tests | 560 adults, average age 58.5 | 87% | about 3 hours a day |
| Framingham 2025, prediabetes | 463 adults | 77% | not reported |
| Framingham 2025, diabetes | 152 adults | 46% | not reported |
The Framingham group was older, average age 58.5, and included anyone from the community with normal blood tests, while Shah’s group was screened to be healthy and not obese, which likely explains much of the gap. Both wore a blinded Dexcom G6, so they couldn’t see their numbers and change their eating to chase them. The Framingham group spent only about 1% of the day above 180, which is why a healthy person on a 70 to 180 report lands in the high 90s.
The sensor’s thumb on the scale
Sensors run high, which pushes time above 140 up and time in range down. In 15 healthy adults, a FreeStyle Libre 2 counted about four times as much time above 140 as fingertip blood did, and still about twice as much after correcting for each person’s fasting offset. Your real time in range is likely a bit higher than your report says.
What to do with your number
- Time from 70 to 140 in the high 80s or more. That fits the healthy groups. Use it to compare your weeks.
- Well below the healthy groups. A sensor can’t diagnose anything, so book a lab A1c and fasting glucose.
- Time under 70. Healthy people spent about 15 minutes a day there on a sensor. A low on a sensor without symptoms isn’t an emergency, but check it with a finger stick.
Put your report next to both healthy groups, with the sensor’s likely bias taken off, in is my sensor running high?
4 sources
- Shah VN and others, Continuous glucose monitoring profiles in healthy nondiabetic participants: a multicenter prospective study, Journal of Clinical Endocrinology and Metabolism, 2019pmc.ncbi.nlm.nih.gov
- Spartano NL and others, Defining continuous glucose monitor time in range in a large, community-based cohort without diabetes, Journal of Clinical Endocrinology and Metabolism, 2025pubmed.ncbi.nlm.nih.gov
- Battelino T and others, Clinical targets for continuous glucose monitoring data interpretation: recommendations from the International Consensus on Time in Range, Diabetes Care, 2019pmc.ncbi.nlm.nih.gov
- Hutchins KM and others, Continuous glucose monitor overestimates glycemia, with the magnitude of bias varying by postprandial test and individual, American Journal of Clinical Nutrition, 2025pmc.ncbi.nlm.nih.gov
