Lab Unit Converter: mg/dL to mmol/L and Back for 30 Markers

Marker

Common values

Anchor points for the selected marker in both unit systems.

mg/dL	mmol/L

Why lab units differ between countries

A lab unit converter translates the same measurement between two systems: US laboratories report most blood tests in conventional units — milligrams per deciliter (mg/dL), nanograms per milliliter (ng/mL) — while laboratories in Europe, Canada, Australia and most of the world use SI units built on molar concentration: millimoles per liter (mmol/L), nanomoles per liter (nmol/L). A glucose of 100 mg/dL and a glucose of 5.55 mmol/L are exactly the same blood sugar.

The conversion factor is fixed by the molecule's molar mass, so the math is exact — not an approximation. What does change between labs is the reference range: always compare a converted value against a range expressed in the same units, ideally the range printed on the lab report itself.

How to use the converter

Pick a marker, type your result in either field, and the other field updates instantly. Use the swap button to flip direction, and the copy button to take the converted value with you. Every marker links to its page in our lab-test reference, where you'll find reference ranges and what high or low values mean.

Conversion factors for 43 lab markers

SI = conventional × factor. Exact molar conversion factors used by clinical laboratories; HbA1c uses the NGSP→IFCC formula (% − 2.15) × 10.929.

Marker	Conventional	SI	Factor	Other units
Glucose	mg/dL	mmol/L	× 0.0555	g/L
HbA1c (glycated hemoglobin)	% (NGSP)	mmol/mol (IFCC)	(% − 2.15) × 10.929	—
Insulin	µIU/mL	pmol/L	× 6.945	—
Total cholesterol	mg/dL	mmol/L	× 0.02586	g/L
LDL cholesterol	mg/dL	mmol/L	× 0.02586	g/L
HDL cholesterol	mg/dL	mmol/L	× 0.02586	g/L
Triglycerides	mg/dL	mmol/L	× 0.01129	g/L
Creatinine	mg/dL	µmol/L	× 88.4	mg/L
Urea / BUN	mg/dL (BUN)	mmol/L (urea)	× 0.357	g/L (urea)
Uric acid	mg/dL	µmol/L	× 59.48	mg/L
Bilirubin (total)	mg/dL	µmol/L	× 17.104	—
Calcium (total)	mg/dL	mmol/L	× 0.2495	mEq/L
Magnesium	mg/dL	mmol/L	× 0.4114	—
Phosphorus	mg/dL	mmol/L	× 0.3229	—
Albumin	g/dL	g/L	× 10	—
Total protein	g/dL	g/L	× 10	—
C-reactive protein (CRP)	mg/dL	mg/L	× 10	—
Serum iron	µg/dL	µmol/L	× 0.1791	—
Ferritin	ng/mL	µg/L	× 1	—
Hemoglobin	g/dL	g/L	× 10	mmol/L
TSH	µIU/mL	mIU/L	× 1	—
Free T4	ng/dL	pmol/L	× 12.87	—
Free T3	pg/mL	pmol/L	× 1.536	—
Testosterone (total)	ng/dL	nmol/L	× 0.0347	—
Estradiol	pg/mL	pmol/L	× 3.671	—
Cortisol	µg/dL	nmol/L	× 27.59	—
Vitamin D (25-OH)	ng/mL	nmol/L	× 2.496	—
Vitamin B12	pg/mL	pmol/L	× 0.7378	—
Folate	ng/mL	nmol/L	× 2.266	—
PSA (total)	ng/mL	µg/L	× 1	—
C-peptide	ng/mL	nmol/L	× 0.331	—
Apolipoprotein B (ApoB)	mg/dL	g/L	× 0.01	—
Apolipoprotein A1 (ApoA1)	mg/dL	g/L	× 0.01	—
Homocysteine	mg/L	µmol/L	× 7.397	—
Progesterone	ng/mL	nmol/L	× 3.18	—
Free testosterone	pg/mL	pmol/L	× 3.467	—
DHEA-S	µg/dL	µmol/L	× 0.02714	—
Prolactin	ng/mL	mIU/L	× 21.2	—
Parathyroid hormone (PTH)	pg/mL	pmol/L	× 0.106	—
Anti-Müllerian hormone (AMH)	ng/mL	pmol/L	× 7.14	—
17-OH progesterone	ng/mL	nmol/L	× 3.03	—
Lactate	mg/dL	mmol/L	× 0.111	—
Ammonia	µg/dL	µmol/L	× 0.587	—

This tool converts units only — it does not interpret results. Reference ranges differ by lab, age and sex; discuss your results with your doctor.

Frequently asked questions

How do I convert glucose from mg/dL to mmol/L?

Multiply by 0.0555 (or divide by 18.02). A glucose of 100 mg/dL equals 5.55 mmol/L; the diabetes threshold of 126 mg/dL equals 7.0 mmol/L.

Why do labs in different countries use different units?

US laboratories kept mass-based conventional units (mg/dL, ng/mL), while most other countries adopted the International System (SI), which measures molar concentration (mmol/L, nmol/L). Both describe the same physical quantity on different scales.

Is a converted value as accurate as the original?

Yes. Conversion factors are exact constants derived from each molecule's molar mass, so nothing is lost — we only round the display to four significant digits. Just make sure you compare the converted value against a reference range in the same units.

Can I compare results from two different labs after converting?

Units convert exactly, but reference ranges and assay methods differ between laboratories. Compare each result against its own lab's reference range, and track trends within one lab where possible.