How to use this mg/dL to mmol/L calculator
This calculator converts lab values between mg/dL and mmol/L in seconds. It is especially useful if your lab report uses one unit system but your doctor, app, or guideline uses the other.
To use it:
- Select the test type (glucose, cholesterol, or triglycerides).
- Choose the conversion direction.
- Enter your value.
- Click Calculate to see the converted number and formula used.
mg/dL vs mmol/L: what is the difference?
Both units describe concentration, but they measure different things:
- mg/dL = milligrams per deciliter (mass concentration)
- mmol/L = millimoles per liter (molecular concentration)
In the United States, glucose is often reported in mg/dL. In many other countries, mmol/L is more common. Because mmol/L is based on molecule count, each substance needs its own conversion factor.
Conversion formulas
The general conversion is:
- mmol/L = mg/dL ÷ factor
- mg/dL = mmol/L × factor
Common factors are:
| Analyte | Factor | Quick rule |
|---|---|---|
| Glucose | 18.0 | Divide by 18 to get mmol/L |
| Cholesterol | 38.67 | Divide by 38.67 to get mmol/L |
| Triglycerides | 88.57 | Divide by 88.57 to get mmol/L |
Examples
Example 1: Glucose
If your glucose is 100 mg/dL:
100 ÷ 18 = 5.56 mmol/L
Example 2: Cholesterol
If total cholesterol is 200 mg/dL:
200 ÷ 38.67 = 5.17 mmol/L
Example 3: Triglycerides
If triglycerides are 150 mg/dL:
150 ÷ 88.57 = 1.69 mmol/L
Reference ranges (glucose quick guide)
These are commonly used fasting glucose ranges for adults, but exact interpretation depends on your clinician and lab:
- Normal: about 70–99 mg/dL (3.9–5.5 mmol/L)
- Prediabetes: about 100–125 mg/dL (5.6–6.9 mmol/L)
- Diabetes range: 126 mg/dL or higher (7.0 mmol/L or higher) on repeat testing
If you use a continuous glucose monitor (CGM), unit conversion can help when comparing app settings, research papers, and clinic instructions.
Why accurate unit conversion matters
- Avoids confusion when traveling or switching labs
- Helps with diabetes tracking and medication decisions
- Makes international clinical guidelines easier to follow
- Prevents charting errors in health journals or spreadsheets
Frequently asked questions
Is this calculator only for blood sugar?
No. This page supports glucose, cholesterol, and triglycerides. Just choose the proper test type first.
Can I convert in both directions?
Yes. You can convert mg/dL to mmol/L and mmol/L back to mg/dL.
Why can’t I use one universal factor for every test?
Because each analyte has a different molecular weight. That changes the relationship between mass and moles.
Should I use this for diagnosis?
Use it as an educational and tracking tool. Diagnosis and treatment decisions should always be made with a qualified healthcare professional.
Final note
If you regularly review lab values, a reliable blood test unit converter saves time and reduces mistakes. Bookmark this page for quick mg/dL and mmol/L conversion whenever you need to compare results across labs, countries, or medical resources.