What Is Normal Blood Sugar? Ranges by Time of Day
For a person without diabetes, normal blood sugar is 70–99 mg/dL (3.9–5.5 mmol/L) after an overnight fast and below 140 mg/dL (7.8 mmol/L) two hours after eating. People with diabetes usually aim for slightly different targets.
Normal blood sugar levels chart
| When measured | Normal (no diabetes) | Typical target with diabetes* |
|---|---|---|
| Fasting / on waking | 70–99 mg/dL (3.9–5.5 mmol/L) | 80–130 mg/dL (4.4–7.2 mmol/L) |
| Before a meal | 70–99 mg/dL | 80–130 mg/dL |
| 1–2 hours after a meal | below 140 mg/dL (7.8 mmol/L) | below 180 mg/dL (10.0 mmol/L) |
| HbA1c (3-month average) | below 5.7% | below 7% for many adults |
*ADA Standards of Care for most non-pregnant adults. Targets are individual — often looser for older adults or people prone to lows, and stricter in pregnancy (see Gestational Diabetes: Screening, Targets and Risks).
How blood sugar moves through the day
In a healthy person, glucose stays in a narrow band. After a meal it rises — usually peaking 30 to 60 minutes after eating, rarely above 140 mg/dL — and returns to baseline within two to three hours as insulin moves glucose into the cells. Overnight the liver releases just enough glucose to keep levels steady. In the early morning, hormones such as cortisol can nudge levels up slightly (the "dawn phenomenon").
Continuous glucose monitors have shown that even healthy people briefly spike above 140 mg/dL after a large, carbohydrate-rich meal. That is not a reason for concern; what matters is the fasting level, the 2-hour level and the long-term average (HbA1c).
When is blood sugar too low or too high?
- Below 70 mg/dL (3.9 mmol/L): low — called hypoglycemia. Below 54 mg/dL (3.0 mmol/L) it is clinically significant. See Low Blood Sugar (Hypoglycemia): Levels & Treatment.
- Fasting 100–125 mg/dL or 140–199 mg/dL two hours after a glucose drink: prediabetes range.
- Fasting 126 mg/dL or more, or 200 mg/dL or more two hours after a glucose drink: diabetes range (confirmed by a repeat test). See High Blood Sugar (Hyperglycemia): Levels & Signs.
Normal blood sugar in children and in pregnancy
The normal ranges above also apply to healthy children and teenagers. Children with type 1 diabetes usually aim for an HbA1c below 7% with individual glucose targets. In pregnancy, targets are tighter: fasting below 95 mg/dL and below 140 mg/dL one hour or 120 mg/dL two hours after meals.
Check your own number
Use the checker on our start page or open a value directly, for example 95, 110 or 140 mg/dL. For the full chart in mg/dL and mmol/L see blood glucose levels chart.
Sources: ADA Standards of Care · ADA: Diagnosis · NIDDK: Diabetes tests and diagnosis · MedlinePlus: Blood glucose test
Check a blood glucose reading
Related guides
- Blood Glucose Levels Chart (mg/dL and mmol/L)
- High Blood Sugar (Hyperglycemia): Levels & Signs
- Low Blood Sugar (Hypoglycemia): Levels & Treatment
- How to Lower High Blood Glucose Quickly
- Raise Low Blood Glucose Fast: The 15-15 Rule
- Blood Glucose Control: How It Works
Educational content only; not medical advice. Follow the treatment plan you have agreed with your doctor or diabetes team. In an emergency, call 911 (US) or your local emergency number.