Estradiol pmol/L To pg/mL Converter
Convert estradiol results between picomoles per litre and picograms per millilitre using the molecular-weight factor for estradiol.
Convert Your Estradiol Result
Converted Result
The converted result will appear here with the formula used.
What This Estradiol Conversion Does
Estradiol, often written as E2, may be reported in pmol/L on many UK and European laboratory reports and in pg/mL on some US reports, fertility articles, older papers or patient forums. The two units describe the same amount of estradiol but use different measurement systems. This converter applies the molecular-weight relationship for estradiol and gives the paired value so that you can compare like with like.
The converter is deliberately limited. It does not interpret a menstrual cycle phase, ovarian stimulation result, menopause status, HRT dose, pregnancy result, endocrine diagnosis or cancer-treatment monitoring result. Reference intervals differ by laboratory, assay, sex registered at birth, age, medication, cycle timing, pregnancy status and clinical purpose. For medical decisions, compare your value with the reference range printed on the report and speak to the clinician who requested the test.
Conversion Formula And Method
pg/mL = pmol/L x 0.27238.
pmol/L = pg/mL / 0.27238.
pmol/L = pg/mL x 3.6713.
The factor comes from the molecular weight of estradiol, about 272.38 g/mol. Because 1 litre equals 1000 millilitres and picomoles and picograms both use metric prefixes, the factor for pmol/L to pg/mL is the molecular weight divided by 1000.
Quick Estradiol Conversion Table
| pmol/L | pg/mL | Plain Reading |
|---|---|---|
| 50 | 13.6 | Unit conversion only; no clinical label is implied. |
| 100 | 27.2 | Often used as a simple check value because the factor is easy to see. |
| 200 | 54.5 | Double 100 pmol/L and the pg/mL value doubles too. |
| 367 | 100.0 | A useful cross-check because 100 pg/mL is about 367 pmol/L. |
| 500 | 136.2 | Round according to the precision used on your report. |
| 1000 | 272.4 | Do not compare this with a reference interval from a different method without caution. |
| 2500 | 681.0 | High numerical values may be expected in some treatment contexts; clinical meaning is separate. |
Worked Examples
UK Report To US Unit
A report states estradiol is 367 pmol/L. The conversion is 367 x 0.27238, giving 99.96 pg/mL, usually written as 100.0 pg/mL if one decimal is selected.
US Article To UK Unit
An article lists 150 pg/mL. The reverse conversion is 150 / 0.27238, giving about 550.7 pmol/L. Use this only to compare units, not to adopt the article’s reference range.
Research Table Rounding
A research table might use two or three decimals. A patient report may use no decimals. Rounding changes presentation, not the underlying conversion.
Laboratory Report Notes
Estradiol assays are method-dependent. Immunoassays and mass-spectrometry methods can differ, especially at low concentrations. Some reports carry flags next to the result; those flags are based on that laboratory’s reference intervals and the clinical details supplied to it. Do not remove a flag just because an online unit converter produces a familiar number in another unit.
If the result is being used for fertility care, HRT review, puberty assessment, cycle tracking, menopause symptoms, oncology monitoring or an endocrine investigation, the timing and medical context matter. The same converted value can mean different things in different people. This page is therefore a reproducible arithmetic aid, not a clinical opinion.
When comparing two reports, check the sample date, sample time, assay method, medication notes and unit before looking at the converted number. A result taken during ovarian stimulation, after a medication change, during pregnancy, after surgery or during acute illness may not be comparable with a routine baseline result. If a value looks unexpected, do not change medication, supplements or clinic instructions because of a converted unit alone. Ask the clinic or GP surgery whether the result should be repeated, reviewed against the local reference interval, or read with other tests such as FSH, LH, progesterone, SHBG or testosterone.
For audit or research work, keep the original unit in the source column and add the converted unit in a separate column. That preserves traceability if a table is checked later. It also avoids a common error where a value is converted twice because the original unit was removed from the dataset.
FAQ
Is 1 pg/mL the same as 3.6713 pmol/L?
Yes, for estradiol. The reverse factor is approximately 3.6713 because it is the reciprocal of 0.27238.
Can I use this for oestradiol?
Yes. Oestradiol is the common UK spelling for estradiol. The molecule and conversion factor are the same.
Does this tell me whether my estradiol is high?
No. The converter does not interpret normality, severity or treatment. Use the reference interval printed on your report and ask your clinician.
Why do laboratories use different units?
Reporting conventions vary between countries, laboratories and publications. pmol/L is common in SI-style reporting, while pg/mL appears in many US resources.
How many decimals should I use?
For patient reports, one decimal or no decimals is usually enough. For research or audit work, match the precision required by the table you are preparing.
Can I use this factor for other hormones?
No. Each hormone has its own molecular weight, so the factor is analyte-specific. Do not use the estradiol factor for progesterone, testosterone or cortisol.
Sources
- International Bureau of Weights and Measures. (2019). The International System of Units (SI), 9th ed. BIPM. https://www.bipm.org/en/publications/si-brochure
- National Center for Biotechnology Information. (n.d.). PubChem Compound Summary for Estradiol. PubChem. https://pubchem.ncbi.nlm.nih.gov/compound/Estradiol
- Lab Tests Online UK. (n.d.). Oestradiol. Lab Tests Online UK. https://labtestsonline.org.uk/tests/oestradiol