Lab Test Unit Converter
The short answer
Choose the analyte, type your value, and the converter switches between US conventional units and SI units using the standard published factors — for example glucose mg/dL × 0.0555 = mmol/L, and total testosterone ng/dL × 0.0347 = nmol/L. Hemoglobin A1c uses the NGSP-to-IFCC master equation instead of a simple multiplier.
- Analytes
- 30
- Directions
- US ↔ SI
- Method
- Published factors
- Cost
- Free
What are the conversion factors for common blood tests?
Multiply the US conventional value by the factor to get the SI value; divide to go back. Factors are fixed per analyte because they derive from molecular weight.
| Analyte | US unit | SI unit | × factor |
|---|---|---|---|
| Glucose | mg/dL | mmol/L | 0.0555 |
| Total cholesterol | mg/dL | mmol/L | 0.02586 |
| LDL cholesterol | mg/dL | mmol/L | 0.02586 |
| HDL cholesterol | mg/dL | mmol/L | 0.02586 |
| Triglycerides | mg/dL | mmol/L | 0.01129 |
| Testosterone (total) | ng/dL | nmol/L | 0.03467 |
| Free testosterone | pg/mL | pmol/L | 3.467 |
| Estradiol | pg/mL | pmol/L | 3.671 |
| Progesterone | ng/mL | nmol/L | 3.18 |
| Prolactin | ng/mL | mIU/L | 21.2 |
| Cortisol | µg/dL | nmol/L | 27.59 |
| DHEA-S | µg/dL | µmol/L | 0.02714 |
| Vitamin D, 25-hydroxy | ng/mL | nmol/L | 2.496 |
| Vitamin B12 | pg/mL | pmol/L | 0.7378 |
| Folate | ng/mL | nmol/L | 2.266 |
| Ferritin | ng/mL | µg/L | 1 |
| Iron | µg/dL | µmol/L | 0.179 |
| Creatinine | mg/dL | µmol/L | 88.42 |
| BUN (urea nitrogen) | mg/dL | mmol/L | 0.357 |
| Uric acid | mg/dL | µmol/L | 59.48 |
| Calcium | mg/dL | mmol/L | 0.2495 |
| Magnesium | mg/dL | mmol/L | 0.4114 |
| Phosphorus | mg/dL | mmol/L | 0.3229 |
| Bilirubin (total) | mg/dL | µmol/L | 17.1 |
| Albumin | g/dL | g/L | 10 |
| Hemoglobin | g/dL | g/L | 10 |
| Insulin | µIU/mL | pmol/L | 6.945 |
| TSH | µIU/mL | mIU/L | 1 |
| PSA | ng/mL | µg/L | 1 |
| C-reactive protein | mg/L | mg/dL | 0.1 |
| Hemoglobin A1c | % (NGSP) | mmol/mol (IFCC) | (A1c − 2.15) × 10.929 |
How do you convert glucose, cholesterol and testosterone by hand?
Glucose
100 mg/dL × 0.0555 = 5.6 mmol/L. The prediabetes fasting band of 100–125 mg/dL is 5.6–6.9 mmol/L.
Cholesterol
LDL 100 mg/dL × 0.02586 = 2.6 mmol/L; 70 mg/dL — a common high-risk target — is 1.8 mmol/L.
Testosterone
300 ng/dL × 0.03467 = 10.4 nmol/L. European labs often quote a 12 nmol/L threshold, which is about 346 ng/dL.
Frequently asked questions
Why do US and international labs use different units?
US labs report most chemistry in mass-per-volume 'conventional' units (mg/dL, ng/mL). Most other countries and the research literature use SI molar units (mmol/L, nmol/L), which count molecules rather than mass. The conversion factor is fixed for each analyte because it comes from its molecular weight.
How do I convert hemoglobin A1c from % to mmol/mol?
A1c isn't a unit swap — the two scales are different standardizations. Use the NGSP/IFCC master equation: mmol/mol = (A1c% − 2.15) × 10.929. So 5.7% ≈ 39 mmol/mol and 6.5% ≈ 48 mmol/mol. The tool also shows estimated average glucose (eAG = 28.7 × A1c − 46.7 mg/dL).
Does converting units change whether my result is normal?
No. The value and the reference range convert by the same factor, so a result inside the range in mg/dL is inside the equivalent range in mmol/L. Just make sure you compare against a range expressed in the same unit.
Why is Lp(a) missing?
Lipoprotein(a) mass (mg/dL) and particle number (nmol/L) don't have a fixed conversion — the ratio depends on the size of the apo(a) isoform and varies between people. Guidelines now recommend reporting Lp(a) in nmol/L, so compare like with like rather than converting.
Which biomarkers does this tool cover?
Which tests give you these numbers?
Physician-authorized, drawn at Quest, Labcorp or BioReference. Results in 1–3 business days for most tests.