Blood sugar levels chart
Normal, prediabetes and diabetes ranges for every common test — plus target ranges once you have a diagnosis, a full A1c conversion table, and the readings that mean stop and get help.
Fasting blood sugar
Measured after at least 8 hours without food or drink other than water — usually first thing in the morning.
Normal
A typical healthy fasting range.
70–99 mg/dL3.9–5.5 mmol/L
Prediabetes (impaired fasting glucose)
Higher than normal, not yet diabetes. Often reversible.
100–125 mg/dL5.6–6.9 mmol/L
Diabetes range
Needs a repeat test on a separate day to confirm.
126 mg/dL or above7.0 mmol/L or above
Ranges follow standard diagnostic criteria for non-pregnant adults. Your own targets may differ — pregnancy, age, kidney disease and certain medications all change the picture. Always confirm your targets with your healthcare provider.
Blood sugar 2 hours after eating
Measured two hours after the first bite of a meal, or two hours into a glucose tolerance test.
Normal
Most people peak under 140 even after a large meal.
Below 140 mg/dLBelow 7.8 mmol/L
Prediabetes (impaired glucose tolerance)
Post-meal numbers often rise before fasting ones do.
140–199 mg/dL7.8–11.0 mmol/L
Diabetes range
A repeat abnormal result confirms the diagnosis.
200 mg/dL or above11.1 mmol/L or above
Ranges follow standard diagnostic criteria for non-pregnant adults. Your own targets may differ — pregnancy, age, kidney disease and certain medications all change the picture. Always confirm your targets with your healthcare provider.
A1c (HbA1c)
A blood test that reflects your average blood sugar over roughly the previous two to three months.
Normal
Average glucose roughly below 117 mg/dL.
Below 5.7%(Below 39 mmol/mol)
Prediabetes
Roughly 117–137 mg/dL average glucose.
5.7–6.4%(39–46 mmol/mol)
Diabetes range
Roughly 140 mg/dL average glucose or higher.
6.5% or above(48 mmol/mol or above)
Ranges follow standard diagnostic criteria for non-pregnant adults. Your own targets may differ — pregnancy, age, kidney disease and certain medications all change the picture. Always confirm your targets with your healthcare provider.
Random (casual) blood sugar
Taken at any time of day without regard to meals — often the first test done when symptoms appear.
Typical
Values vary with what and when you last ate.
Below 140 mg/dLBelow 7.8 mmol/L
Worth investigating
Ask for a fasting glucose or A1c to clarify.
140–199 mg/dL7.8–11.0 mmol/L
Diabetes range
With classic symptoms, this alone can diagnose diabetes.
200 mg/dL or above11.1 mmol/L or above
Ranges follow standard diagnostic criteria for non-pregnant adults. Your own targets may differ — pregnancy, age, kidney disease and certain medications all change the picture. Always confirm your targets with your healthcare provider.
- Normal
- Prediabetes
- Diabetes range
A1c chart and estimated average glucose
A1c reflects roughly three months of average glucose. These equivalents use the standard conversion, eAG = (28.7 × A1c) − 46.7.
| A1c | Average glucose (mg/dL) | Average glucose (mmol/L) | Category |
|---|---|---|---|
| 5.0% | 97 | 5.4 | Normal |
| 5.5% | 111 | 6.2 | Normal |
| 6.0% | 125 | 6.9 | Prediabetes |
| 6.5% | 140 | 7.8 | Diabetes range |
| 7.0% | 154 | 8.6 | Diabetes range |
| 7.5% | 169 | 9.4 | Diabetes range |
| 8.0% | 183 | 10.2 | Diabetes range |
| 9.0% | 212 | 11.8 | Diabetes range |
| 10.0% | 240 | 13.3 | Diabetes range |
| 11.0% | 269 | 14.9 | Diabetes range |
| 12.0% | 298 | 16.6 | Diabetes range |
Target ranges if you already have diabetes
Diagnostic thresholds answer whether you have diabetes. These answer where to aim afterwards. They are general adult starting points — yours may be deliberately tighter or looser.
Fasting / before meals
80–130 mg/dL (4.4–7.2 mmol/L)
General adult target for people with diabetes.
Peak after meals
Below 180 mg/dL (10.0 mmol/L)
Measured 1–2 hours after the start of a meal.
A1c
Below 7% for many adults
Targets are individualized — older adults may be set higher.
Time in range (CGM)
Over 70% between 70–180 mg/dL
Applies if you use a continuous glucose monitor.
Seek urgent care
Readings and symptoms that need help today
- Blood sugar above 240 mg/dL (13.3 mmol/L) with ketones in your urine
- Repeated vomiting or an inability to keep fluids down
- Deep, rapid breathing, or breath that smells fruity
- Confusion, extreme drowsiness or difficulty staying awake
- Blood sugar above 300 mg/dL (16.7 mmol/L) on two readings in a row
These can indicate diabetic ketoacidosis or a hyperosmolar hyperglycemic state. Both are emergencies — contact your care team or emergency services rather than waiting to see if it settles.
Free tool
Want to log your own readings against these ranges?
Free Blood Sugar Monitor color-codes every entry against the same thresholds, tracks your averages and estimated A1c, and exports a summary you can hand to your clinician.
Frequently asked questions
What is a normal blood sugar level?
For a non-pregnant adult without diabetes, a normal fasting blood sugar is 70–99 mg/dL (3.9–5.5 mmol/L), a normal reading two hours after eating is below 140 mg/dL (7.8 mmol/L), and a normal A1c is below 5.7%.
What A1c is considered diabetes?
An A1c of 6.5% or above on two separate tests indicates diabetes. 5.7% to 6.4% indicates prediabetes, and below 5.7% is normal.
What is a dangerous blood sugar level?
Above 240 mg/dL (13.3 mmol/L) with ketones present needs same-day medical advice. Above 300 mg/dL (16.7 mmol/L) is urgent and above 400 mg/dL (22.2 mmol/L) usually needs emergency care. Below 70 mg/dL is hypoglycemia and below 54 mg/dL is an emergency.
How do I convert blood sugar between mg/dL and mmol/L?
Divide mg/dL by 18 to get mmol/L, and multiply mmol/L by 18 for the reverse. For example, 126 mg/dL equals 7.0 mmol/L.
Want the detail behind these numbers? Read Normal Blood Sugar Levels Chart: Fasting, After Eating & A1c.