Lab results · molar ratio
Testosterone to estradiol ratio calculator
See how your total testosterone compares to your estradiol, calculated as a true molar ratio rather than dividing two differently scaled units.
This is a calculated ratio, not a diagnosis, and there is no single number this tool treats as "optimal."
How this calculator works
Total testosterone (entered in ng/dL) is converted to picomoles per liter using testosterone's molecular weight, and estradiol (entered in pg/mL) is converted to picomoles per liter using its own molecular weight. Dividing the two molar values gives a true, dimensionless ratio.
The conversion factors used
Testosterone: 1 ng/dL equals 34.7 pmol/L. Estradiol: 1 pg/mL equals about 3.67 pmol/L. Both come directly from each hormone's molecular weight, not an estimate.
Why this matters on TRT
Testosterone aromatizes into estradiol, and clinicians often look at both values together rather than testosterone alone when reviewing bloodwork. This tool only does the arithmetic so the comparison is apples to apples; it does not tell you whether your specific ratio is a problem.
Frequently asked questions
What is the testosterone to estradiol (T:E2) ratio?
It is the molar ratio between your total testosterone and your estradiol (E2) level, both converted to the same unit (picomoles per liter) so the comparison is apples to apples rather than two different unit systems.
Is there an ideal T:E2 ratio?
There is no single, universally agreed optimal ratio that applies to everyone. This tool calculates your number from your lab values; interpreting what it means for you is a conversation for a clinician who knows your full picture, not a fixed cutoff.
Why convert to molar units instead of using ng/dL and pg/mL directly?
Testosterone and estradiol have different molecular weights, so dividing a ng/dL value by a pg/mL value does not produce a true ratio, it just divides two differently scaled numbers. Converting both to picomoles per liter first gives a ratio that is actually comparable across labs and units.
Why does estradiol matter on TRT?
Testosterone converts to estradiol in the body through an enzyme called aromatase. Monitoring both values together, rather than testosterone alone, is part of how clinicians track that conversion and watch for estrogen-related side effects.
Method
Molar conversion using the molecular weights of testosterone (288.42 g/mol) and estradiol (272.38 g/mol), the standard approach used throughout clinical chemistry to express a true molar ratio between two different hormones.