mmol/L to mg/dL Calculator

This calculator converts concentration values between mmol/L (millimoles per litre) and mg/dL (milligrams per decilitre), the two units used to report blood test results such as blood glucose, cholesterol, triglycerides, urea, calcium and magnesium. New Zealand, Australia, the United Kingdom and most of Europe report these results in mmol/L, while the United States and Japan use mg/dL, so you need this conversion whenever you compare a NZ lab report with an imported glucose meter or an overseas reference range. You start by selecting the substance from the dropdown, since each one has its own molecular weight and therefore its own conversion factor, then choose the direction you want to convert and type in your value. The calculator instantly shows the converted result, the input you entered, and the exact conversion factor used, along with the underlying formula and a step-by-step breakdown of the calculation. A worked example using a fasting blood glucose of 5.5 mmol/L (99.1 mg/dL) is shown alongside your own figures, and a reference table lists common values such as fasting glucose targets and cholesterol thresholds in both units for quick comparison. A swap button lets you flip the conversion direction instantly. This tool performs the mathematical conversion only; it does not offer medical advice, and you should discuss what any result means for your health with a doctor or other qualified healthcare professional.

Standard conversion Molecular weights from IUPAC. Conversion factors are fixed constants, not subject to change.

1. Select Substance

Substance (sets conversion factor)

Direction

Value in mmol/L

mmol/L

2. Result

Value in mg/dL

mg/dL

Conversion factor used

factor

Formula

Conversion Results

Result
99.1
mg/dL

Input

5.5

mmol/L

Factor

18.0182

Molecular weight / 10

Common Reference Values

Measurement	mmol/L	mg/dL	Context

Calculation Steps

SubstanceBlood glucose

Input value5.5 mmol/L

Directionmmol/L to mg/dL

Conversion factor18.0182

Calculation5.5 x 18.0182 = 99.1001

Result99.1 mg/dL

Worked Example (Defaults)

SubstanceBlood glucose

Input5.5 mmol/L

Factor18.0182

Calculation5.5 x 18.0182

Result99.1 mg/dL

Note: Enter a value above to see your conversion.

How the mmol/L to mg/dL Conversion Works

Both mmol/L (millimoles per litre) and mg/dL (milligrams per decilitre) measure the concentration of a substance in blood or another fluid. They differ in the unit used to express the amount of substance. The conversion between them depends on the molecular weight of the specific substance being measured.

The formula is:

mg/dL = mmol/L x (molecular weight / 10)
mmol/L = mg/dL / (molecular weight / 10)

The division by 10 converts between litres and decilitres (1 L = 10 dL). This means the conversion factor is substance-specific and you cannot use a single number for all tests.

Conversion Factors by Substance

Substance	Molecular Weight (g/mol)	Factor (MW / 10)	Example
Glucose (blood sugar)	180.182	18.0182	5.5 mmol/L = 99.1 mg/dL
Cholesterol (total, LDL, HDL)	386.65	38.665	5.0 mmol/L = 193.3 mg/dL
Triglycerides	885.43	88.543	1.5 mmol/L = 132.8 mg/dL
Urea	60.06	6.006	7.0 mmol/L = 42.0 mg/dL
Creatinine*	113.12	0.011312*	80 umol/L = 0.9 mg/dL
Calcium	40.08	4.008	2.5 mmol/L = 10.02 mg/dL
Magnesium	24.31	2.431	1.0 mmol/L = 2.43 mg/dL

* Creatinine is measured in umol/L in New Zealand rather than mmol/L, so it uses a different base unit from the substances above. Multiply umol/L by 0.011312 to get mg/dL (for example, 80 umol/L = 0.9 mg/dL). Because its base unit differs, creatinine is shown here for reference only and is not part of the substance selector above. Urea is converted using the standard molecular-weight factor (60.06 / 10 = 6.006), giving whole-molecule urea rather than blood urea nitrogen (BUN).

Blood Glucose: NZ vs US Reference Ranges

Category	NZ/UK (mmol/L)	US (mg/dL)
Normal fasting glucose	4.0 to 5.9	72 to 106
Pre-diabetes (impaired fasting)	6.0 to 6.9	108 to 124
Diabetes diagnosis (fasting)	7.0 or above	126 or above
Hypoglycaemia	Below 4.0	Below 72
Target post-meal (2 hr, diabetic)	Below 8.5	Below 153

Why Different Countries Use Different Units

The United States, Japan, and some other countries adopted mg/dL as the standard for reporting blood glucose and cholesterol when clinical laboratory testing became widespread in the mid-20th century. New Zealand, Australia, the United Kingdom, Canada, and most of Europe adopted the International System of Units (SI), which uses mmol/L, as part of broader metrication in medicine during the 1970s and 1980s.

This means that if you read an American diabetes study, a US glucose monitor, or a US food label about blood sugar, the numbers will typically be about 18 times larger than the equivalent NZ value. A reading of 100 mg/dL (US normal fasting) is approximately 5.6 mmol/L in NZ terms.

Practical Tips for Using This Calculator

If you are comparing an imported glucose monitor to a NZ laboratory result, use the glucose factor (18.0182).
For cholesterol, the same factor (38.665) applies to total cholesterol, LDL, and HDL since they are all cholesterol molecules.
Triglycerides use a much larger factor (88.543) because the molecule is much heavier than cholesterol.
If your lab report uses different units from your doctor's reference chart, use this calculator to reconcile them.
Always confirm clinical interpretation with a healthcare professional; this calculator provides the mathematical conversion only.

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Sources and method: Molecular weights from IUPAC (International Union of Pure and Applied Chemistry) and PubChem. Conversion formula: mg/dL = mmol/L x (molecular weight / 10). Blood glucose reference ranges: Ministry of Health New Zealand / Diabetes New Zealand. Cholesterol reference ranges: Heart Foundation of New Zealand.

This calculator provides the mathematical unit conversion only. It does not constitute medical advice. Clinical interpretation of laboratory results should be discussed with a qualified healthcare professional. Reference ranges may vary between laboratories.

Frequently asked questions

How do you convert mmol/L to mg/dL for blood glucose?

To convert blood glucose from mmol/L to mg/dL, multiply the mmol/L value by 18.0182. This factor comes from the molecular weight of glucose (180.182 g/mol) divided by 10. For example, a fasting blood glucose of 5.5 mmol/L equals 5.5 x 18.0182 = 99.1 mg/dL. To convert back, divide the mg/dL value by 18.0182.

Why is the conversion factor different for cholesterol and glucose?

The conversion factor between mmol/L and mg/dL depends on the molecular weight of the substance being measured. Glucose has a molecular weight of 180.182 g/mol, giving a factor of 18.0182. Cholesterol (MW 386.65 g/mol) uses a factor of 38.665, and triglycerides (MW 885.43 g/mol) use 88.543. The formula is: mg/dL = mmol/L x (molecular weight / 10).

Which countries use mmol/L and which use mg/dL for blood glucose?

New Zealand, Australia, the United Kingdom, Canada, and most of Europe report blood glucose in mmol/L. The United States, Japan, and several other countries use mg/dL. When reading international diabetes resources, glucose monitors, or research papers, you may need to convert between these units. A fasting glucose target of under 6.0 mmol/L in NZ is equivalent to under 108 mg/dL.

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