Q
What should my fasting glucose be?
⚡ Quick answer
Optimal: 70-90 mg/dL. Normal: under 100. Prediabetic: 100-125. Diabetic: 126+.
Fasting glucose targets:
- Optimal: 70-90 mg/dL (3.9-5.0 mmol/L) — best metabolic health
- Normal: under 100 mg/dL (under 5.6 mmol/L)
- Prediabetic: 100-125 mg/dL (5.6-6.9 mmol/L) — early warning
- Diabetic: 126+ mg/dL (7.0+ mmol/L) on two separate tests
For people with existing diabetes, doctors often target under 130 fasting and under 180 after meals.
Key context: morning glucose can spike 20-30 mg/dL due to the dawn phenomenon (cortisol release at dawn). Test at the same time daily for trends. A single high reading is not diabetes.
More important than fasting glucose alone: HbA1c (3-month average), fasting insulin (early sign of resistance), and post-meal glucose response.
Read our full evidence-based guide on diabetes for the complete picture.
View Full Guide →We write from peer-reviewed research and clinical guidance. These links let you read the underlying evidence yourself rather than taking our word for it.