Blood sugar converter
Use this converter to translate a blood glucose reading between mg/dL and mmol/L. You can also choose whether the reading was fasting, before a meal, after a meal, or random so the result shows the most relevant general reference point.
This is a conversion and education tool. It does not diagnose diabetes, adjust insulin, or tell you how much food or medicine to take.
Convert a blood sugar reading
Enter a glucose value, choose the unit from your meter or lab, and select the context so the result can show the most relevant reference range.
Converted blood glucose
Elevated fasting lab range
U.S. unit
100mg/dL
International unit
5.6mmol/L
This falls in the CDC prediabetes fasting lab range. One home reading does not diagnose prediabetes, but repeated results are worth discussing with a clinician.
Formula and caution: The converter uses 1 mmol/L glucose = 18.016 mg/dL. Reference labels are general education only and do not diagnose diabetes or adjust insulin, food, or medicine doses.
How to use the converter
Enter the number from your blood glucose meter, CGM, or lab report. Choose the unit printed beside the number, then select the context that best matches when the reading was taken.
If you are comparing a lab result, use the timing from the lab order or report. If you are checking at home, write down the result with the time, food, activity, illness, and medication timing because those details can change what the number means.
Formula
Blood glucose is commonly reported in mg/dL in the United States and mmol/L in many other countries. The conversion comes from the molecular weight of glucose:
| Conversion | Formula |
|---|---|
| mmol/L to mg/dL | mmol/L x 18.016 |
| mg/dL to mmol/L | mg/dL / 18.016 |
Example: 5.6 mmol/L x 18.016 = about 101 mg/dL. A reading of 180 mg/dL / 18.016 = about 10.0 mmol/L.
Reference points used
The tool uses common CDC and ADA reference points:
| Context | General reference point |
|---|---|
| Low blood sugar | Below 70 mg/dL |
| Fasting lab result | Normal below 100 mg/dL, prediabetes 100-125 mg/dL, diabetes threshold 126 mg/dL or above |
| Before a meal for many nonpregnant adults with diabetes | 80-130 mg/dL |
| 1-2 hours after the start of a meal for many nonpregnant adults with diabetes | Less than 180 mg/dL |
| Random lab result with symptoms | Diabetes threshold 200 mg/dL or above |
These are not personal targets. Your clinician may set different goals based on age, pregnancy, diabetes type, medicines, hypoglycemia risk, kidney disease, heart disease, and other factors.
Safety notes
Blood sugar below 70 mg/dL is generally considered low. If you use insulin or medicines that can cause lows, follow the low-glucose plan your clinician gave you. Seek urgent help if symptoms are severe, the person is confused or unconscious, or carbohydrates cannot be kept down.
If you have diabetes, are sick, and your blood sugar is 240 mg/dL or above, CDC guidance says to check ketones and call your doctor if ketones are high. Diabetic ketoacidosis can be life-threatening and needs immediate treatment.
Do not use this converter for gestational diabetes diagnosis, pediatric targets, medication adjustment, or emergency decisions. Use it to understand units and to prepare a clearer question for your healthcare team.
Related tools
If glucose checks happen around daily medicines, add the routine to the medication schedule builder. If you also track supplements or prescriptions, use the refill calculator before supplies run low.
Common questions
Is 5.5 mmol/L a normal blood sugar?
It converts to about 99 mg/dL. For a fasting lab result, that is within the CDC normal fasting range. For another context, compare it with the target your clinician gave you.
What is 180 mg/dL in mmol/L?
180 mg/dL is about 10.0 mmol/L. ADA and CDC patient guidance often use less than 180 mg/dL as a typical 1-2 hour after-meal target for many nonpregnant adults with diabetes.
Does one high reading mean I have diabetes?
No. Diabetes diagnosis usually requires lab testing and clinical review. A repeated high home reading, a fasting reading at or above 126 mg/dL, or a random reading at or above 200 mg/dL with symptoms should be discussed with a healthcare professional.
What blood sugar is considered low?
Blood sugar below 70 mg/dL is generally considered low. Follow your prescribed plan for low glucose, and seek urgent help for severe symptoms, confusion, unconsciousness, or inability to keep carbohydrates down.
