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Lab Unit Converter: mmol/L to mg/dL and More
To convert glucose from mmol/L to mg/dL, multiply by 18 (more exactly 18.02): 5.5 mmol/L is about 99 mg/dL. To go the other way, multiply mg/dL by 0.0555. Every lab test has its own factor, set by the molar mass of the substance, so this converter lists 20 common ones, such as cholesterol, creatinine, testosterone, estradiol and vitamin D, and shows the math.
Prepared by Prospyr · Reviewed October 3, 2026 · Free, no sign-up, runs in your browser
Glucose: 100 mg/dL equals
5.55mmol/L
Rounded for reporting: 5.6 mmol/L.
Unit conversion only. It does not interpret a result. Reference ranges depend on the lab, assay and patient; use the range printed on the report.
All conversion factors
| Test | Conventional to SI | Multiply by | SI to conventional |
|---|---|---|---|
| mg/dL → mmol/L | 0.0555 | × 18.018 | |
| mg/dL → mmol/L | 0.02586 | × 38.6698 | |
| mg/dL → mmol/L | 0.02586 | × 38.6698 | |
| mg/dL → mmol/L | 0.02586 | × 38.6698 | |
| mg/dL → mmol/L | 0.01129 | × 88.574 | |
| mg/dL → µmol/L | 88.4 | × 0.0113 | |
| mg/dL → mmol/L urea | 0.357 | × 2.8011 | |
| mg/dL → µmol/L | 59.48 | × 0.0168 | |
| mg/dL → mmol/L | 0.2495 | × 4.008 | |
| mg/dL → mmol/L | 0.4114 | × 2.4307 | |
| mg/dL → µmol/L | 17.1 | × 0.0585 | |
| ng/dL → nmol/L | 0.0347 | × 28.8184 | |
| pg/mL → pmol/L | 3.671 | × 0.2724 | |
| ng/mL → nmol/L | 3.18 | × 0.3145 | |
| µg/dL → nmol/L | 27.59 | × 0.0362 | |
| ng/mL → nmol/L | 2.496 | × 0.4006 | |
| pg/mL → pmol/L | 0.7378 | × 1.3554 | |
| ng/mL → nmol/L | 2.266 | × 0.4413 | |
| ng/mL → pmol/L | 2.247 | × 0.445 | |
| g/dL → g/L | 10 | × 0.1 |
How lab unit conversion works
U.S. labs usually report results in conventional units (mg/dL, ng/mL) and most of the rest of the world reports SI units (mmol/L, nmol/L). The two describe the same blood level. Converting between them is multiplication by a fixed factor for each test.
For a result in mass per volume, the SI value is the mass divided by the molar mass. That is why each test has its own number: mmol/L = mg/dL × 10 ÷ molar mass in g/mol. For glucose that is 10 ÷ 180.16 = 0.0555. The factors in this tool match the molar masses listed on PubChem to within 0.3%. Two exceptions: ferritin assumes about 445,000 g/mol, and hemoglobin g/dL to g/L is a plain ×10.
- To SI: conventional value × factor
- From SI: SI value ÷ factor
Worked examples: mmol/L to mg/dL and other common conversions
| Result | Math | Converted |
|---|---|---|
| Glucose 100 mg/dL | 100 × 0.0555 | 5.55 mmol/L |
| Glucose 5.5 mmol/L | 5.5 ÷ 0.0555 | 99 mg/dL |
| Total cholesterol 200 mg/dL | 200 × 0.02586 | 5.17 mmol/L |
| Creatinine 1.0 mg/dL | 1.0 × 88.4 | 88.4 µmol/L |
| Testosterone 15 nmol/L | 15 ÷ 0.0347 | 432 ng/dL |
| Vitamin D 30 ng/mL | 30 × 2.496 | 74.9 nmol/L |
| Estradiol 50 pg/mL | 50 × 3.671 | 183.6 pmol/L |
Pick the test, enter the value and read the answer, or scroll to the table of all factors and tap a test name to load it.
Testosterone, estradiol and vitamin D unit conversion
Hormone and vitamin results are where practices see the most unit confusion, because a patient's outside lab may report in a different system from yours. Testosterone is often ng/dL in the U.S. and nmol/L abroad, estradiol is pg/mL or pmol/L, and 25-hydroxy vitamin D is ng/mL or nmol/L. The converter handles all three in both directions.
For the vitamin you take, as opposed to the blood level, see the IU to mcg converter. For general mass conversions, use the mg to mcg converter.
Using one set of units across your practice
Results that arrive in mixed units are easy to chart wrong. Prospyr's aesthetic EMR keeps lab results with the patient record, and the charting workflow lets your team note the unit with each value so the next provider reads it the same way.
Frequently asked questions
How do you convert mmol/L to mg/dL for glucose?
Multiply mmol/L by 18.02 (about 18). 5.5 mmol/L × 18.02 = 99 mg/dL. To convert mg/dL to mmol/L, multiply by 0.0555, so 100 mg/dL = 5.55 mmol/L.
Why is the mg/dL to mmol/L factor different for each test?
A mmol is a count of molecules and a mg is a weight, so the factor depends on how heavy one molecule of the substance is. Glucose is 180.16 g/mol and cholesterol is 386.65 g/mol, which is why glucose uses 0.0555 and cholesterol uses 0.02586. Heavier molecules have smaller factors.
How do I convert testosterone from nmol/L to ng/dL?
Divide nmol/L by 0.0347, which is the same as multiplying by about 28.8. 15 nmol/L ÷ 0.0347 = 432 ng/dL. To convert ng/dL to nmol/L, multiply by 0.0347.
How do I convert vitamin D from ng/mL to nmol/L?
Multiply ng/mL by 2.496, which most references round to 2.5. 30 ng/mL × 2.496 = 74.9 nmol/L. The NIH Office of Dietary Supplements states that 1 nmol/L equals 0.4 ng/mL, and 1 ng/mL is about 2.5 nmol/L.
How do I convert estradiol from pg/mL to pmol/L?
Multiply pg/mL by 3.671. 50 pg/mL × 3.671 = 183.6 pmol/L. To go from pmol/L to pg/mL, divide by 3.671, or multiply by 0.2724.
How do I convert creatinine from mg/dL to µmol/L?
Multiply mg/dL by 88.4. A creatinine of 1.0 mg/dL is 88.4 µmol/L. To convert µmol/L to mg/dL, divide by 88.4.
Will this tell me if a result is normal?
No. It only converts units. Reference ranges depend on the lab, the assay, and the patient, so use the range printed on the lab report and let the provider interpret the result. Some tests, such as insulin, are left out because their unit conversion is not settled enough for a one-factor tool.
Sources and scope
- PubChem (National Library of Medicine): compound records for molar masses
Molar masses used to check each factor: glucose 180.16, cholesterol 386.7, creatinine 113.12, testosterone 288.4, estradiol 272.4, progesterone 314.5, cortisol 362.5, uric acid 168.11, bilirubin 584.7, 25-hydroxyvitamin D3 400.6, cyanocobalamin 1355.4, folic acid 441.4, urea 60.056, triolein 885.4, magnesium 24.305, calcium 40.08 g/mol. The link opens glucose; search the others by name.
- NIH Office of Dietary Supplements: Vitamin D Fact Sheet for Health Professionals
States that serum 25(OH)D is reported in nmol/L and ng/mL, with 1 nmol/L = 0.4 ng/mL and 1 ng/mL about 2.5 nmol/L.
- Knopp JL et al. Insulin Units and Conversion Factors. J Diabetes Sci Technol, 2019 (PMC6501531)
Why insulin is left out of this converter: two different conversion factors circulate, differing by about 15%.
Unit conversion only, not medical advice. It does not interpret results or give reference ranges. Factors are the commonly published values, verified against molar mass; some assays differ slightly, and ferritin in pmol/L varies by assay.