Gly LogNormal fasting blood sugar and how to check it
Fasting blood sugar is measured after at least 8 hours without food. Most people check it in the morning before breakfast, and it is the most basic number in blood sugar tracking.
Fasting blood sugar ranges at a glance
| Fasting blood sugar (mg/dL) | Category |
|---|---|
| Under 100 | Normal |
| 100 – 125 | Prediabetes (impaired fasting glucose) |
| 126 or higher | Meets the diagnostic threshold for diabetes |
Diabetes is not diagnosed from a single reading at home. It is confirmed with lab tests, usually repeated on another day or combined with other tests such as A1C.
If you have diabetes: a common target
A pre-meal (fasting) target often recommended for adults with diabetes is 80–130 mg/dL. Your own target may be different depending on age, risk of low blood sugar, and medications, so use the number your care team gave you.
How to get an accurate fasting reading
- Have nothing but water for at least 8 hours after dinner.
- Check after waking up, before breakfast, coffee, or exercise.
- Wash your hands with soap and dry them completely. Fruit juice or water left on your fingers can change the reading.
- Write down the number and the time right away — times get fuzzy when you log later.
Check at the same time each day
With fasting blood sugar, the trend over days and weeks matters more than any single day. Checking at a similar time each morning keeps your numbers comparable.
This article is general health information and does not replace diagnosis or treatment. Targets and how often to check differ from person to person, so follow your care team first. If you have symptoms of low blood sugar or readings far outside your range, contact your care team right away.
Reference: American Diabetes Association (ADA) Standards of Care
Last updated 2026-10-26