mmol/L to mg/dL Converter

Blood tests report how much of a substance is in a fixed amount of blood. Some countries count the number of molecules (mmol/L). Others weigh the substance (mg/dL). The conversion depends on the substance, because every molecule has a different weight.

What mmol/L and mg/dL Measure

mmol/L means millimoles per liter, which counts molecules. mg/dL means milligrams per deciliter, which counts weight. A result of 5.5 mmol/L glucose and 99 mg/dL glucose describe the same blood sample. This tool changes the unit only. It does not change what the result says.

The Formula

To go from mmol/L to mg/dL, multiply by the molecular weight of the substance divided by 10. Glucose weighs 180.16 g/mol¹, so its factor is 18.016. Cholesterol and triglycerides have their own factors, which match the ones CDC uses in its national survey data² ³. Creatinine is reported in µmol/L, and a lab table divides by 88.4 to reach mg/dL⁴.

Glucose: mg/dL = mmol/L x 18.016

Total, HDL or LDL cholesterol: mg/dL = mmol/L x 38.67

Triglycerides: mg/dL = mmol/L x 88.57

Creatinine: mg/dL = µmol/L / 88.4

How This Calculator Computes Your Result

Pick the substance, type your number, and use the swap button to go the other way. Nothing is rounded until the end. Glucose, cholesterol and triglycerides show as whole mg/dL numbers, and creatinine shows two decimals. Going from mg/dL to mmol/L, glucose shows one decimal and the lipids show two. For glucose the tool also shows the answer with the factor of 18 that many clinics use, which differs by less than 0.1%.

Example: 5.5 mmol/L x 18.016 = 99.09, shown as 99 mg/dL.

What Your Result Means

The tool can add a reference band to your converted number. These are general adult ranges, and one reading is not a diagnosis. A doctor makes any diagnosis.

For glucose, the band only appears if you tick the fasting box (no food or drink except water for at least 8 hours). The American Diabetes Association lists a fasting plasma glucose below 100 mg/dL as normal, 100 to 125 mg/dL as prediabetes, and 126 mg/dL or higher as the diabetes range⁵. A single result is not enough, because diagnosis needs confirmed testing.

For cholesterol and triglycerides the tool uses the US National Cholesterol Education Program (ATP III) bands⁶.

Quick Reference Tables

These values were computed with the same factors the tool uses.

Sanity check: glucose in mg/dL is about 18 times the mmol/L number, cholesterol about 39 times and triglycerides about 89 times.

Why Each Substance Has Its Own Factor

The factor is the weight of one mole of the substance, divided by 10. Glucose is a small molecule, so its factor is small. Cholesterol is larger, so its factor is about twice as big. Triglycerides are a mix of fats of slightly different sizes, so 88.57 is an approximation. Labs also round their factors. One large lab uses 18.02 for glucose, 38.61 for cholesterol and 88.5 for triglycerides⁴. These differ from ours by under 0.2%.

Why Countries Use Different Units, and Why It Matters

In the United States most lab results use conventional units such as mg/dL. Other countries mostly report in the international system of units (SI), such as mmol/L⁷. Canada, for example, gives blood glucose targets in mmol/L⁸. The UK, Australia and much of Europe follow the same SI habit. Both systems are correct.

The risk is a misread number. A fasting glucose of 7.0 is in the diabetes range in mmol/L, but 7 mg/dL would be far below any normal reading. A cholesterol of 5.0 mmol/L is 193 mg/dL, but the glucose factor by mistake gives 90. If a result looks far too high or low, check the unit beside it.