How to Use the Hormone Unit Conversion Calculator
Select the hormone from the dropdown, choose the conversion direction, and enter the value from your lab report. The calculator automatically applies the correct factor for that hormone and unit pair.
Different hormones use different molecular weights and reporting conventions. This is why testosterone, estradiol, cortisol, and thyroid hormones cannot all use one universal conversion factor.
Supported Hormones and Unit Pairs
The calculator focuses on common hormone conversions seen in routine lab reports, hormone panels, fertility testing, thyroid testing, and adrenal testing.
| Hormone | Unit pair | Conversion factor |
|---|---|---|
| Testosterone | ng/dL ⇄ nmol/L | 1 ng/dL = 0.0347 nmol/L |
| Estradiol (E2) | pg/mL ⇄ pmol/L | 1 pg/mL = 3.672 pmol/L |
| Progesterone | ng/mL ⇄ nmol/L | 1 ng/mL = 3.180 nmol/L |
| Cortisol | µg/dL ⇄ nmol/L | 1 µg/dL = 27.59 nmol/L |
| Free T3 | pmol/L ⇄ pg/mL | 1 pmol/L = 0.651 pg/mL |
| Free T4 | pmol/L ⇄ ng/dL | 1 pmol/L = 0.0777 ng/dL |
| 25-OH Vitamin D | ng/mL ⇄ nmol/L | 1 ng/mL = 2.496 nmol/L |
| Aldosterone | ng/dL ⇄ pmol/L | 1 ng/dL = 27.74 pmol/L |
Hormone Conversion Formulas
Many hormone conversions move between mass concentration and molar concentration. The exact formula depends on the unit pair and molecular weight of the hormone.
nmol/L = ng/dL × 10 ÷ 288.42 pmol/L = pg/mL × 1000 ÷ 272.38 nmol/L = µg/dL × 10000 ÷ 362.46 Example Hormone Conversions
A testosterone result of 300 ng/dL converts to about 10.40 nmol/L. An estradiol result of 100 pg/mL converts to about 367 pmol/L. A cortisol result of 10 µg/dL converts to about 276 nmol/L.
These examples show why selecting the correct hormone matters. A value may look similar across reports, but the unit pair and molecular weight determine the true converted result.
Why Hormone Unit Conversion Matters
Laboratories in different countries often report the same hormone in different units. US reports may use ng/dL, ng/mL, pg/mL, or µg/dL, while international reports often use nmol/L, pmol/L, or other SI-style units.
Converting the unit helps compare old and new lab reports, review international reference ranges, prepare for specialist visits, and avoid confusing one reporting system with another.
Common Mistakes to Avoid
Do not use a testosterone factor for estradiol, progesterone, cortisol, or thyroid hormones. Each hormone has its own molecular weight and preferred unit pair.
Do not mix total and free hormone tests without checking the test name. Total testosterone and free testosterone, for example, can use different units and different clinical reference ranges.
Always compare a converted value with a matching reference range. A reference range written for ng/dL should not be used with nmol/L unless it has also been converted.
Frequently Asked Questions
Can one conversion factor work for every hormone?
No. Hormone conversions depend on the specific hormone and unit pair. Testosterone, estradiol, progesterone, cortisol, Free T3, and Free T4 all require different factors.
How do I convert testosterone ng/dL to nmol/L?
Multiply testosterone in ng/dL by about 0.0347. For example, 300 ng/dL is about 10.40 nmol/L.
How do I convert estradiol pg/mL to pmol/L?
Multiply estradiol in pg/mL by about 3.672. For example, 100 pg/mL is about 367 pmol/L.
Does this calculator replace a hormone reference range?
No. It only converts units. Hormone interpretation depends on the test name, timing, cycle phase, age, sex, medications, symptoms, assay method, and the reference range printed on your report.
Can I use this for thyroid hormones?
Yes, the calculator includes Free T3 and Free T4. For more focused thyroid pages, use the dedicated Free T3, Free T4, and TSH calculators linked below.
Conclusion
This hormone unit conversion calculator helps you compare common hormone lab units across different reports and countries. Use it for accurate unit conversion, then rely on a qualified healthcare professional to interpret what the result means for your health.