Blood Sugar Converter: mg/dL to mmol/L
mg/dL ÷ 18 = mmol/L, and mmol/L × 18 = mg/dL. So 100 mg/dL is 5.6 mmol/L, and 7.0 mmol/L is 126 mg/dL. Type in either box below, or paste a list.
One reading
A list of readings
Nothing you type or paste leaves your browser.
Quick reference
| mg/dL | mmol/L | Why it matters |
|---|---|---|
| 54 | 3.0 | ADA hypoglycemia level 2 line |
| 70 | 3.9 | ADA hypoglycemia line; CGM range starts |
| 80 | 4.4 | Low end of before-meal target |
| 99 | 5.5 | Top of the fasting range under prediabetes |
| 100 | 5.6 | Fasting prediabetes range starts |
| 126 | 7.0 | Fasting diabetes range starts |
| 130 | 7.2 | High end of before-meal target |
| 140 | 7.8 | 2-hour lab test: prediabetes range starts |
| 180 | 10.0 | After-meal peak target; CGM range ends |
| 200 | 11.1 | 2-hour lab test: diabetes range |
| 250 | 13.9 | CDC: check ketones if sick |
| 300 | 16.7 | CDC: emergency care if it stays here |
How it works
- Type or paste. Either box converts into the other as you type.
- We apply one factor. The tool divides by 18 or multiplies by 18, then rounds: mmol/L to one decimal place, mg/dL to a whole number.
- You compare with published ranges. The blood sugar chart and your care team’s targets use the same units you convert here.
The math: mmol/L = mg/dL ÷ 18; mg/dL = mmol/L × 18.
Glucose molar mass 180.16 g/mol (mg/dL ÷ 18 = mmol/L)
Why two units exist
Glucose can be counted by weight (milligrams in a tenth of a liter, mg/dL) or by number of molecules (millimoles in a liter, mmol/L). The United States reports by weight. Most other countries report by molecules. The two never change what a reading means, only how it is written, so a travel meter or a relative’s lab report from abroad is easy to read once you know the factor.
Check the unit printed on a meter before you act on a number, because a reading of 7 means very different things in the two units. A1C also has its own unit pairs (percent and mmol/mol). For those, use the A1C calculator. If you wear a CGM and want to see what your average means as an A1C-style number, try the GMI calculator.
Frequently asked questions
How do I convert mg/dL to mmol/L?
Divide by 18. For example, 126 mg/dL ÷ 18 = 7.0 mmol/L. The factor comes from the molar mass of glucose, about 180 g/mol.
How do I convert mmol/L to mg/dL?
Multiply by 18. For example, 5.5 mmol/L × 18 = 99 mg/dL. Results are rounded to a whole number, so a value converted back and forth can differ by 1.
Which unit does the United States use?
The United States uses mg/dL on meters, sensors and lab reports. Canada, the United Kingdom, Australia and much of Europe use mmol/L. Some apps and meters let you switch.
Why is the factor sometimes written as 18.016?
The exact molar mass of glucose is 180.16 g/mol, which gives 18.016. Most sources round to 18, and so do we. The difference is under 0.1% and does not change what a reading means.
Can I paste a whole list from my meter?
Yes. Paste readings separated by spaces, commas or new lines, choose the direction, and the tool converts each one. Values that are not numbers or fall outside 20 to 600 mg/dL are skipped and counted so you can check.
Information only, not medical advice. Your care team may set different targets for you, and only a lab test ordered by a clinician can diagnose diabetes or prediabetes. See our medical disclaimer.
Sources
- ADA Standards of Care in Diabetes—2026, Section 6: Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises
- NIDDK: Diagnosis of Diabetes and Prediabetes
- Glucose, PubChem (molar mass 180.16 g/mol)
Last reviewed: by the Diabetes Blogs editorial team. Information only, not medical advice.
