Blood sugar (glucose) is measured in mg/dL in the US and mmol/L in most other countries. This converter lets you instantly switch between units and see how your reading compares to normal, pre-diabetes, and diabetes reference ranges.
Blood Glucose Converter
Blood Sugar Reference Ranges
| Timing | Normal | Pre-diabetes | Diabetes |
|---|---|---|---|
| Fasting | <100 mg/dL <5.6 mmol/L |
100–125 mg/dL 5.6–6.9 mmol/L |
≥126 mg/dL ≥7.0 mmol/L |
| 2-hr Post-meal | <140 mg/dL <7.8 mmol/L |
140–199 mg/dL 7.8–11.0 mmol/L |
≥200 mg/dL ≥11.1 mmol/L |
| Hypoglycemia | Below 70 mg/dL (3.9 mmol/L) — low blood sugar alert | ||
How to Use the Blood Sugar Converter
This blood sugar converter lets you instantly switch between the two units used worldwide for measuring blood glucose: mg/dL (used in the US) and mmol/L (used in the UK, Canada, Australia, and most of Europe).
How to Convert
Type any value in either field — the other updates automatically. Enter a US reading in mg/dL and instantly see the international equivalent, or enter a mmol/L value and see the US equivalent. The converter uses the standard factor of 18.018.
Understanding the Reference Ranges
The reference table shows fasting and post-meal targets for normal, pre-diabetes, and diabetes categories per ADA and WHO guidelines. A fasting reading below 100 mg/dL (5.6 mmol/L) is normal. A reading of 100–125 mg/dL (5.6–6.9 mmol/L) fasting indicates pre-diabetes. Diabetes is typically diagnosed at 126 mg/dL (7.0 mmol/L) or higher on two separate occasions.
Hypoglycemia Warning
Blood sugar below 70 mg/dL (3.9 mmol/L) is considered low (hypoglycemia) and requires prompt action. Symptoms include shakiness, confusion, sweating, and rapid heartbeat. If you experience these symptoms, consume fast-acting carbohydrates and consult a healthcare provider if episodes recur.
FAQ
Is this blood sugar converter free?
Yes, completely free with no signup required. All conversions run in your browser.
Is my health data safe?
Yes, all calculations run locally in your browser. No data is sent to any server.
What is the formula to convert mg/dL to mmol/L?
Divide mg/dL by 18.018 to get mmol/L. For example, 180 mg/dL ÷ 18.018 = 9.99 mmol/L. To convert the other way, multiply mmol/L by 18.018.
What is a normal fasting blood sugar level?
A normal fasting blood sugar is below 100 mg/dL (5.6 mmol/L). Pre-diabetes is 100–125 mg/dL (5.6–6.9 mmol/L). Diabetes is diagnosed at 126 mg/dL (7.0 mmol/L) or higher on two separate tests.
What is a normal blood sugar 2 hours after eating?
Normal post-meal (2-hour) blood glucose is below 140 mg/dL (7.8 mmol/L). Pre-diabetes is 140–199 mg/dL (7.8–11.0 mmol/L). Values of 200 mg/dL (11.1 mmol/L) or higher indicate diabetes.
Why do some countries use mg/dL and others use mmol/L?
The US uses mg/dL (milligrams per deciliter), while most other countries use mmol/L (millimoles per liter). Both measure the same thing — blood glucose concentration — just in different units. The conversion factor is 18.018.