Fasting Blood Sugar: What the Normal Range Is
A fasting blood sugar of 70 to 99 mg/dL is considered normal. A higher reading is not read as a conclusion on its own.
Fasting blood sugar is measured in the morning after a night without food. It shows the level of sugar in your blood with nothing recently eaten.
The ranges
| Category | Fasting sugar (mg/dL) |
|---|---|
| Normal | 70 – 99 |
| Prediabetes | 100 – 125 |
| Diabetes threshold | 126 and above |
Ranges vary slightly between laboratories, so always read the range printed on your own report.
A single reading above 126 is not a diagnosis by itself. Doctors usually repeat it or read it alongside HbA1c.
Preparing for the test
- Nothing to eat for 8 to 10 hours — water is fine
- No tea, coffee or milk either
- Avoid an unusually heavy meal the night before
- If you take regular medication, ask your doctor before the test
Fasting beyond twelve hours is not necessary and can itself shift the result in some people.
Is fasting sugar enough on its own?
Often not. Some people have a normal fasting result while their after-meal sugar runs high. That is why doctors frequently add a two-hour post-meal test or HbA1c.
When the reading is low
A reading below 70 — especially with sweating, trembling, anxiety or dizziness — should not be brushed aside. It is seen more often in people taking diabetes medication.
Frequently asked questions
How long should I fast?+
8 to 10 hours. Water is fine; tea, coffee and milk are not.
Does one reading of 130 mean diabetes?+
No. A single report is not a diagnosis — doctors repeat it or read it with HbA1c.
My fasting sugar is fine but it rises after meals. What now?+
That is not unusual. Doctors typically add a two-hour post-meal test or HbA1c.
Is a 14-hour fast better?+
No — beyond twelve hours is unnecessary, and a very long fast can itself shift the result.