Check what a blood sugar reading means. This free tool shows which standard reference range your fasting, post-meal, random or HbA1c result falls into — informational only, not a diagnosis.
For HbA1c, enter a percentage (e.g. 5.5). Reference ranges follow common ADA guidance for non-pregnant adults.
Reference ranges are general and for non-pregnant adults; pregnancy, children and some conditions use different targets. Always confirm with a healthcare professional.
How the Blood Sugar Level Checker Works
The Blood Sugar Level Checker doesn’t diagnose anything — it takes the reading you enter and shows you which commonly published clinical reference range it falls into, based on the test type you select.
Formula: The tool compares your Reading against fixed reference bands for the selected Test type. For Fasting: below 70 mg/dL = Below normal (low), 70–99 mg/dL = Normal, 100–125 mg/dL = Prediabetes range, 126 mg/dL and above = Diabetes range. For 2-hours-after-eating or Random tests: below 70 mg/dL = Below normal (low), 70–139 mg/dL = Normal, 140–199 mg/dL = Prediabetes range, 200 mg/dL and above = Diabetes range. For HbA1c: below 5.7% = Normal, 5.7–6.4% = Prediabetes range, 6.5% and above = Diabetes range. If you enter mmol/L, the tool converts it using mg/dL = mmol/L × 18.0182 before comparing it to these bands.
- Test type — which test you took: fasting (no food 8+ hours), 2 hours after eating, random (any time), or HbA1c (3-month average)
- Reading — the numeric result from your test, entered in mg/dL or mmol/L (HbA1c is always entered as a percentage)
- Glucose units — a toggle between mg/dL and mmol/L for glucose readings so the tool compares your number to the correct band
Example Scenarios
| Test type | Reading | Reference category |
|---|---|---|
| Fasting | 95 mg/dL | Normal |
| Fasting | 110 mg/dL | Prediabetes range |
| Fasting | 65 mg/dL | Below normal (low) |
| 2 hours after eating | 160 mg/dL | Prediabetes range |
| Random | 220 mg/dL | Diabetes range |
| HbA1c | 5.4% | Normal |
Blood Sugar Level Checker FAQ
What’s the difference between a fasting, post-meal and random blood sugar test?
A fasting test measures glucose after at least 8 hours without food, a post-meal (2-hour) test measures it after eating, and a random test can be taken any time. Each uses its own normal range because glucose naturally rises after meals.Does this tool diagnose diabetes or prediabetes?
No. It only shows which published reference range your entered number falls into. Diagnosing diabetes or prediabetes requires repeated testing, clinical context and a doctor’s interpretation — a single reading here is informational only, not a diagnosis.What is considered a normal fasting blood sugar level?
Using common ADA-based reference ranges for non-pregnant adults, a fasting glucose under 100 mg/dL is generally categorized as normal, 100–125 mg/dL as the prediabetes range, and 126 mg/dL or higher as the diabetes range. Your own healthy target may differ.Why is the normal range different for post-meal readings than fasting readings?
Blood sugar rises temporarily after eating as food is digested, so a 2-hour post-meal reading is naturally higher than a fasting one. The checker uses a higher normal ceiling (under 140 mg/dL) for post-meal and random readings than for fasting (under 100 mg/dL).How do I convert my glucose reading between mg/dL and mmol/L?
Use the units toggle and enter your number as shown on your meter or lab report — the tool converts automatically using mg/dL = mmol/L × 18.0182. HbA1c is always entered as a percentage and doesn’t use this conversion.What should I do if my reading falls in the prediabetes or diabetes range?
Treat it as a prompt to talk to a doctor, not a diagnosis. A single reading can be affected by illness, stress or timing, and only a healthcare professional can confirm a diagnosis using proper testing and follow-up.Related Calculators
If you’re curious how a single reading fits into a bigger picture, the Diabetes Risk Calculator looks at everyday risk factors beyond one number, while the Glycemic Load Calculator can help you see how specific meals may affect blood sugar swings. For another commonly tested area of metabolic health, try the Thyroid Function Checker.