How to Convert pmol/L to pg/mL
pmol/L and pg/mL both measure concentration, but they use different systems. pmol/L is a molar concentration, while pg/mL is a mass concentration. Because the conversion moves between moles and mass, the molecular weight of the substance is required.
pg/mL = (pmol/L x molecular weight) / 1000 pmol/L = (pg/mL x 1000) / molecular weight This is why an estradiol conversion factor is different from a vitamin B12, insulin, PTH, or thyroid hormone conversion factor.
Why Molecular Weight Matters
A picomole counts molecules. A picogram measures mass. Larger molecules weigh more per mole, so the same pmol/L value becomes a larger pg/mL value for high-molecular-weight substances.
For example, estradiol has a molecular weight of about 272.38 g/mol, so 367 pmol/L is about 100 pg/mL. Vitamin B12 has a much larger molecular weight, so its pmol/L to pg/mL conversion factor is very different.
Supported Molecules and Conversion Factors
Select the correct molecule before comparing your result with a reference range. The calculator uses the molecular weight shown below.
| Molecule | Molecular weight | 1 pmol/L equals | Common use |
|---|---|---|---|
| Estradiol (E2) | 272.38 g/mol | 0.2724 pg/mL | Reproductive hormone monitoring and estrogen assessment |
| Progesterone | 314.47 g/mol | 0.3145 pg/mL | Ovulation, luteal phase, and pregnancy-related testing |
| Testosterone | 288.42 g/mol | 0.2884 pg/mL | Androgen and endocrine assessment |
| Cortisol | 362.46 g/mol | 0.3625 pg/mL | Adrenal and stress hormone assessment |
| Free T3 (Triiodothyronine) | 650.97 g/mol | 0.651 pg/mL | Thyroid function testing |
| Free T4 (Thyroxine) | 776.87 g/mol | 0.7769 pg/mL | Thyroid function testing |
| Parathyroid Hormone (PTH) | 9500 g/mol | 9.5 pg/mL | Calcium, phosphate, and parathyroid assessment |
| Insulin | 5808 g/mol | 5.808 pg/mL | Glucose metabolism and endocrine testing |
| Vitamin B12 (Cobalamin) | 1355.37 g/mol | 1.3554 pg/mL | B12 status and anemia evaluation |
| Folate (Folic Acid) | 441.4 g/mol | 0.4414 pg/mL | Folate status and anemia evaluation |
Estradiol pmol/L to pg/mL Examples
Estradiol is one of the most common reasons people search for this conversion. Many labs report estradiol in pmol/L, while many US reference ranges use pg/mL.
| pmol/L | pg/mL | Context |
|---|---|---|
| 37 pmol/L | 10.08 pg/mL | Low male/postmenopausal example |
| 73 pmol/L | 19.88 pg/mL | Low-normal male example |
| 110 pmol/L | 29.96 pg/mL | Mid-normal male example |
| 184 pmol/L | 50.12 pg/mL | Lower therapeutic/HRT example |
| 367 pmol/L | 99.97 pg/mL | Mid follicular/HRT example |
| 734 pmol/L | 199.93 pg/mL | Luteal phase example |
Always compare estradiol values against the reference interval from your own lab, because ranges differ by sex, age, cycle phase, pregnancy, therapy, and assay method.
Step-by-Step Example
Suppose your estradiol result is 367 pmol/L and you want pg/mL.
- Choose Estradiol (E2) in the calculator.
- Use the formula: pg/mL = pmol/L x molecular weight / 1000.
- Calculate: 367 x 272.38 / 1000 = 99.97 pg/mL.
For the reverse conversion, 100 pg/mL estradiol is approximately 367.13 pmol/L.
Common Lab Tests Using pmol/L and pg/mL
These units are common for hormones, thyroid markers, vitamins, and peptide hormones measured in small concentrations.
- Estradiol: often reported in pmol/L internationally and pg/mL in US-style references.
- Free T3 and Free T4: may appear in pmol/L or pg/mL depending on the laboratory. For thyroid-specific examples, use the Free T3 Unit Conversion Calculator.
- PTH and insulin: peptide hormones where molecular weight creates larger conversion factors.
- Vitamin B12 and folate: nutritional markers that may use pmol/L, pg/mL, or related units.
Frequently Asked Questions
Is pmol/L to pg/mL a 1:1 conversion?
No. pmol/L to pg/mL is not 1:1 because it converts molar concentration to mass concentration. Molecular weight is required.
What is the estradiol conversion from pmol/L to pg/mL?
For estradiol, pg/mL is approximately pmol/L divided by 3.671, or pmol/L multiplied by 0.27238.
Can I use the estradiol factor for testosterone or thyroid hormones?
No. Each substance has a different molecular weight. Select the correct molecule before converting.
Why do some calculators only work for estradiol?
Estradiol is a common use case, but the general pmol/L to pg/mL formula can work for many molecules when the molecular weight is known.
Are these conversions medical advice?
No. This tool converts units only. Diagnosis and treatment decisions require clinical context and a qualified healthcare provider.
Conclusion
The best pmol/L to pg/mL calculator must account for molecular weight. A single universal factor would be inaccurate for mixed lab substances.
Use the calculator above to select the correct molecule, convert your value, and compare results more confidently across lab reports and reference ranges.