Enter the time in range percentage your CGM app reports (the share of the day between 70 and 180 mg/dL, or 3.9 to 10.0 mmol/L) and see what it means in hours, against the consensus targets, and as an approximate A1C.
In range per day:
Approximate A1C: (rough research-based estimate, see below)
The consensus targets
The 2019 international consensus on CGM data (Battelino et al., Diabetes Care 2019) recommends these goals for most adults with type 1 or type 2 diabetes:
| Metric | Most adults | Older or higher-risk adults |
|---|---|---|
| Time in range (70-180 mg/dL) | more than 70% | more than 50% |
| Time below 70 mg/dL | less than 4% | less than 1% |
| Time below 54 mg/dL | less than 1% | not separately specified |
| Time above 180 mg/dL | less than 25% | less than 50% |
| Time above 250 mg/dL | less than 5% | less than 10% |
During pregnancy the consensus uses a tighter 63 to 140 mg/dL (3.5 to 7.8 mmol/L) range with a goal of more than 70% inside it. Targets are always individual: the right goal for you is the one agreed with your care team.
TIR in hours, and the A1C it roughly maps to
Published analyses that compared CGM data with laboratory A1C found a simple rule of thumb: 70% time in range corresponds to an A1C of about 7%, and every 10% of TIR shifts A1C by roughly 0.5%. The estimates below (and in the calculator above) use exactly that relationship, so treat them as orientation, not as a lab result.
| Time in range | Hours per day | Approximate A1C |
|---|---|---|
| 40% | 9 h 36 min | 8.5% |
| 50% | 12 h 0 min | 8.0% |
| 60% | 14 h 24 min | 7.5% |
| 70% | 16 h 48 min | 7.0% |
| 80% | 19 h 12 min | 6.5% |
| 90% | 21 h 36 min | 6.0% |
Want the full story of what TIR is and why it became the headline CGM metric? Read Time in Range explained. To translate a lab A1C into average glucose (or the other way round), use the A1C calculator.
Frequently asked questions
What is a good time in range?
The international consensus recommends spending more than 70% of the day between 70 and 180 mg/dL (3.9 to 10.0 mmol/L) for most adults with type 1 or type 2 diabetes, with less than 4% of the day below 70 mg/dL. For older adults or people at higher risk of lows, more than 50% in range is the recommended, more conservative goal.
How many hours a day is 70% time in range?
70% of 24 hours is 16.8 hours, so about 16 hours 48 minutes in range. A useful rule of thumb: every 10% of time in range equals about 2.4 hours of the day.
What glucose range does time in range use?
The standard range is 70 to 180 mg/dL (3.9 to 10.0 mmol/L). During pregnancy a tighter range of 63 to 140 mg/dL (3.5 to 7.8 mmol/L) is used. Some people also track a personal, tighter range with their care team, but published targets refer to the standard range. You can convert any threshold with our blood sugar unit converter.
Does time in range replace A1C?
No, they complement each other. A1C compresses about three months into a single number, while time in range shows how much of the day you actually spend in range and reveals the swings an average can hide. Published analyses map roughly each 10% change in TIR to about 0.5% of A1C, which is what our A1C calculator and the estimate on this page are based on.
How does Sugar Sense track time in range?
Automatically. Sugar Sense calculates your time in range from your CGM readings for today and the last 7, 30 or 90 days, using the same thresholds that drive your alerts, and it is completely free. You can even build streaks for days that hit your TIR goal.
More free tools
This tool is for education only. It is not medical advice, it does not replace laboratory testing, and it must never be used for insulin dosing or other treatment decisions. Always work with your healthcare team. See our full medical disclaimer.
