mmol/L to mg/dL Calculator

Convert blood glucose, cholesterol, triglycerides, urea, calcium, or magnesium lab values from millimoles per liter (mmol/L) to milligrams per deciliter (mg/dL) using each substance's molar-mass conversion factor.

Quick Facts

Core formula
mg/dL = mmol/L x molar mass (g/mol) / 10
Each analyte has its own molar mass, so the multiplier changes by substance.
Glucose factor
1 mmol/L glucose = 18.0182 mg/dL
Often rounded to x18 for quick mental math; use the exact factor for reporting.

Your Results

Calculated
Result in mg/dL
-
Converted value
Value entered
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Original mmol/L input
Conversion factor used
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mg/dL per 1 mmol/L
Rounded value
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Whole-number mg/dL, typical report precision

Ready

Choose a substance and enter the mmol/L value, then calculate.

About the mmol/L to mg/dL conversion

Blood test results are reported in millimoles per liter (mmol/L) in most of the world and in milligrams per deciliter (mg/dL) in the United States and a few other countries. The two units describe the same physical quantity - molar concentration versus mass concentration - so converting between them is a matter of multiplying by the substance's molar mass, not a clinical judgment. This calculator performs that conversion for common blood chemistry analytes.

How the conversion works

The general formula is: mg/dL = mmol/L x molar mass (g/mol) / 10. A millimole of any substance has a mass in milligrams equal to its molar mass, so multiplying the mmol/L concentration by the molar mass gives mg/L; dividing by 10 rescales from per-liter to per-deciliter. Because every analyte has a different molar mass, each one needs its own multiplier - there is no single universal "mmol/L to mg/dL" number.

Conversion factors for common analytes

  • Glucose: x18.0182 (molar mass 180.182 g/mol). A fasting glucose of 5.5 mmol/L converts to about 99.1 mg/dL.
  • Total, HDL, and LDL cholesterol: x38.67 (molar mass 386.65 g/mol). A total cholesterol of 5.2 mmol/L converts to about 201.1 mg/dL.
  • Triglycerides: x88.57 (based on the average molar mass used for mixed triglycerides).
  • Urea / blood urea nitrogen (BUN): x2.801, the factor used when a urea result is reported as BUN-equivalent mg/dL.
  • Calcium: x4.008 (molar mass 40.08 g/mol). Magnesium: x2.431 (molar mass 24.31 g/mol).

Interpreting a converted value

  • Converting units does not change the underlying measurement - a correctly converted value should match what the same sample would show on a report using the other unit system.
  • Reference ranges also depend on the unit, so compare a converted value against a reference range expressed in the same unit (mg/dL ranges for mg/dL results, mmol/L ranges for mmol/L results).
  • This calculator does not interpret whether a value is high, low, or normal for you - it only performs the arithmetic conversion between units.

Important disclaimer

This tool performs a unit conversion only; it does not diagnose, treat, or manage any medical condition. Discuss what a specific lab value means for you with the clinician or laboratory that issued the report.

Frequently Asked Questions

How do I convert a lab value from mmol/L to mg/dL?
Multiply the mmol/L value by the substance's molar mass in g/mol, then divide by 10: mg/dL = mmol/L x molar mass / 10. Each analyte has a different molar mass, so the multiplier is different for glucose, cholesterol, triglycerides, urea, calcium, and magnesium. This calculator applies the correct published factor once you pick the substance.
Why is the glucose conversion factor 18.0182?
Glucose has a molar mass of about 180.182 g/mol. Dividing by 10 to convert from mg/L to mg/dL gives 18.0182, so 1 mmol/L of glucose equals 18.0182 mg/dL. Many clinicians round this to 18 for quick mental estimates, which introduces a small rounding error at higher values.
Can I use this calculator for a lab test that is not listed?
Yes, if you know the substance's molar mass. Select Custom, then enter the conversion factor as molar mass in g/mol divided by 10. If you are not sure of the correct factor for a specific analyte, check the lab report or a clinical reference rather than guessing, since using the wrong factor gives a meaningless result.

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