What is a good Time in Range?

For many non-pregnant adults with type 1 or type 2 diabetes, the international consensus target is more than 70% of the day in range (70–180 mg/dL, or 3.9–10.0 mmol/L), with less than 4% below 70 mg/dL and less than 25% above 180 mg/dL. Targets differ for pregnancy, older adults, and higher-risk groups, so they should be individualized with a clinician.

What does Time in Range mean?

Time in Range (TIR) is the percentage of time a person's glucose stays within a target band, most often 70–180 mg/dL, measured by a continuous glucose monitor. It captures the shape of glucose control across the day in a way a single HbA1c average cannot.

Calculator · glucose metrics

CGM Calculator: Average Glucose to A1c, and Time in Range

Tool · Updated September 2026

✓ Medically reviewed by Dr. Jerome Fischer, MD, endocrinologist · 5 Jun 2026

Two numbers people most often want from a CGM: the A1c your sensor average implies, and how much of the day you spend in range. Enter your average glucose for the first and your hours per band for the second.

Average glucose to A1c (GMI)

Your CGM app shows an average glucose for the last 14 days. Enter it and read the GMI, the A1c that average implies. What GMI is, and why it can differ from a lab A1c.

CGM average glucose

Units

GMI (A1c it implies)

–

IFCC units

–

Formula (Bergenstal et al., 2018): GMI (%) = 3.31 + 0.02392 × mean glucose (mg/dL).

Time in range calculator

Enter the hours you spent in each glucose band over a typical day and see time in range, below range and above range against the international consensus targets.

Very low, below 54 mg/dL (3.0 mmol/L)

Low, 54–69 mg/dL (3.0–3.8)

In range, 70–180 mg/dL (3.9–10.0)

High, 181–250 mg/dL (10.1–13.9)

Very high, above 250 mg/dL (13.9)

Total entered: 24.0 h

Time in range

–

Below range (<70)

–

Above range (>180)

–

One more thing. Add Endobits as a preferred source and our newest guides land first in your Google results.

Illustrative and educational only. These consensus targets apply to many non-pregnant adults with type 1 or type 2 diabetes. Targets are different for pregnancy, older or high-risk adults, and other situations, and should be individualized with your clinician. This tool is not a diagnosis and is not a reason to change treatment on your own.

What the targets mean

The 2019 international consensus recommends, for many non-pregnant adults with diabetes: >70% Time in Range (70–180 mg/dL), <4% below 70 mg/dL and <1% below 54 mg/dL, and <25% above 180 mg/dL with <5% above 250 mg/dL. Each additional 5% of Time in Range is generally considered clinically meaningful. Time in Range describes the shape of control across the day, which a single HbA1c can hide, see Why Time in Range isn't enough and HbA1c vs CGM.

See your full glucose curve

Time in Range is one summary. The continuous trace shows exactly when and why glucose leaves range.

Check your glucose

Related: HbA1c & GMI calculator · Glossary · All resources

Get Endobits in your Google results. Add us as a preferred source and our newest guides surface first in Top Stories.

Sources

Battelino T, et al. Clinical targets for continuous glucose monitoring data interpretation: recommendations from the international consensus on Time in Range, Diabetes Care, 2019.
American Diabetes Association, CGM & Time in Range.