Progesterone–Estrogen Ratio Calculator

The Progesterone–Estrogen Ratio Calculator estimates the ratio between progesterone and estradiol using serum blood test results to help clinicians and patients assess hormonal balance. This tool is essential for evaluating fertility status, menstrual health, and potential estrogen dominance. Whether you are monitoring a luteal phase, checking for hormone imbalances, or reviewing endocrine health, this calculator provides clear clinical insights.

Serum progesterone concentration (Range: 0.1 - 60 ng/mL)
Serum estradiol (E2) concentration (Range: 5 - 5000 pg/mL)
Select the phase to enable clinical interpretation.

How Progesterone-to-Estradiol Ratio Is Calculated

The Progesterone-to-Estradiol Ratio (P:E Ratio) is a clinical marker used to evaluate the relative balance between these two key hormones. This ratio helps identify conditions like estrogen dominance or progesterone deficiency, which can affect menstrual cycles and fertility.

Ratio = (Progesterone [ng/mL] × 1000) ÷ Estradiol [pg/mL]

Where:

  • Progesterone: Measured in nanograms per milliliter (ng/mL).
  • Estradiol: Measured in picograms per milliliter (pg/mL).
  • 1000: Conversion factor to align units (1 ng = 1000 pg).

The calculation first converts progesterone levels to match the unit scale of estradiol. By dividing the converted progesterone value by the estradiol value, you get a single number representing the hormonal balance. This method is standard in functional medicine and reproductive endocrinology.

While the calculation provides a numerical value, interpretation depends heavily on the specific phase of the menstrual cycle or the patient's life stage (e.g., postmenopausal).

What Your Progesterone-to-Estradiol Ratio Means

Your calculated ratio helps determine if your sex hormones are in balance relative to each other. This is particularly useful during the luteal phase of the menstrual cycle.

For Fertility (Luteal Phase): A ratio between 100 and 300 is generally considered optimal for supporting a healthy pregnancy. A ratio below 100 often indicates estrogen dominance, which may contribute to symptoms like PMS, fibroids, or heavy periods.

For General Balance: A ratio significantly above 300 may suggest progesterone dominance, which is less common but can occur with supplementation or specific ovarian issues. Tracking this ratio over time can help clinicians adjust hormone replacement therapies or fertility treatments.

Important

Hormone levels fluctuate daily. A single test result may not represent your overall hormonal health. Always interpret results in the context of your full clinical picture.

Calculation logic verified using publicly available standards.

View our Accuracy & Reliability Framework →