mg/dL ↔ mmol/L Calculator
Convert lab values between mg/dL and mmol/L for common blood tests.
Tip: Different analytes use different conversion factors, so always choose the correct test type.
How to convert mg/dL to mmol/L (and back)
The units mg/dL (milligrams per deciliter) and mmol/L (millimoles per liter) both describe concentration, but they are based on different ideas: one is mass-based, the other is mole-based. In medical reports, both are common depending on country and lab system.
This calculator lets you convert in either direction. Just enter your value, pick the conversion direction, choose your analyte, and click calculate.
Common conversion factors
The factor changes by substance because molecular weight is different.
- Glucose: 1 mmol/L = 18 mg/dL
- Cholesterol (Total, LDL, HDL): 1 mmol/L = 38.67 mg/dL
- Triglycerides: 1 mmol/L = 88.57 mg/dL
Formulas
- mg/dL → mmol/L: mmol/L = mg/dL ÷ factor
- mmol/L → mg/dL: mg/dL = mmol/L × factor
Worked examples
Glucose example
If fasting glucose is 100 mg/dL, then:
100 ÷ 18 = 5.56 mmol/L
Cholesterol example
If total cholesterol is 200 mg/dL, then:
200 ÷ 38.67 = 5.17 mmol/L
Triglycerides example
If triglycerides are 150 mg/dL, then:
150 ÷ 88.57 = 1.69 mmol/L
Quick reference table
| Test | mg/dL | mmol/L (approx.) |
|---|---|---|
| Glucose | 70 | 3.89 |
| Glucose | 100 | 5.56 |
| Glucose | 126 | 7.00 |
| Total Cholesterol | 200 | 5.17 |
| Triglycerides | 150 | 1.69 |
Why the same test has different units
Countries like the United States often report in mg/dL, while many others use mmol/L. Neither is “more correct” in all situations; they are just different representations. In research papers, international references, and when comparing results across regions, unit conversion is essential.
Important note
This tool is for educational and convenience purposes. Lab interpretation depends on context: fasting status, medications, age, chronic conditions, and lab-specific reference ranges. Always discuss abnormal values with a qualified clinician.
Frequently asked questions
Is this calculator only for glucose?
No. It supports glucose, cholesterol, triglycerides, and a custom factor option.
Why do my rounded results differ slightly from my lab app?
Small differences come from rounding rules and decimal precision. Clinical interpretation usually focuses on meaningful ranges rather than tiny decimal variations.
Can I use a custom factor?
Yes. Choose “Custom factor” and enter the mg/dL-per-mmol/L factor supplied by your reference source.