PG/E2 Ratio Calculator — Progesterone to Estradiol Ratio
Enter your serum progesterone and estradiol levels — in any common unit — and get the PG/E2 ratio with a visual guide to mid-luteal phase adequacy. Units are auto-converted; a ratio ≥ 100 is often considered a minimum target during the luteal phase.
Progesterone unit
ng/mL
Estradiol unit
pg/mL
Very low — may indicate estrogen dominance
- 1
Progesterone (ng/mL)
15 - 2
Estradiol (pg/mL)
150 - 3
PG/E2 ratio
(15 ÷ 150) × 100 = 10A mid-luteal ratio ≥ 100 is commonly cited as the minimum adequate target.
How does this calculator work?
PG/E2 ratio = (Progesterone in ng/mL ÷ Estradiol in pg/mL) × 100. A mid-luteal ratio ≥ 100 is commonly cited as a minimum target; > 200 is typical with supplementation. The calculator converts nmol/L or pmol/L inputs automatically. Results are educational — interpret with your doctor.
Formula
How this is calculated
The PG/E2 ratio compares the dominant hormones of the luteal phase: progesterone (produced by the corpus luteum after ovulation) and estradiol (produced mainly by the ovarian follicle). The formula standardises both to their most common clinical units — ng/mL for progesterone and pg/mL for estradiol — and multiplies by 100 to avoid very small decimals. If your lab reports nmol/L or pmol/L, the calculator converts automatically (1 ng/mL progesterone ≈ 3.18 nmol/L; 1 pg/mL estradiol ≈ 3.67 pmol/L).
A ratio below 100 during the mid-luteal phase (roughly days 19–22 of a 28-day cycle) is sometimes interpreted as suggesting estrogen dominance or inadequate luteal-phase support, particularly in fertility medicine. A ratio of 100–200 is generally cited as adequate for natural cycles. Ratios above 200–300 are common in patients on supplemental progesterone (e.g. during IVF). These thresholds are not universally standardised and vary between clinicians and laboratories.
Important limitations: reference ranges differ between labs, assay methods (immunoassay vs mass spectrometry) and cycle phases. A single ratio is only one data point — pattern over serial draws is more informative. This tool does not replace individualised clinical assessment.
Frequently asked questions
A commonly cited target is ≥ 100 during the mid-luteal phase (cycle days 19–22). Some fertility specialists aim for ≥ 200 when using supplemental progesterone. Below 50 is generally considered very low. These are guidelines — your clinician may use different thresholds depending on your laboratory and treatment protocol.
A ratio below 100 in the luteal phase may indicate that estrogen is relatively elevated compared to progesterone (often called "estrogen dominance") or that the corpus luteum is not producing adequate progesterone to support implantation. It does not diagnose a condition on its own — your doctor will consider other hormones, symptoms and cycle timing.
Progesterone is typically measured in ng/mL and estradiol in pg/mL. Since 1 ng = 1000 pg, dividing ng/mL by pg/mL gives a very small number (e.g. 0.10 for typical values). Multiplying by 100 scales the result to a more readable range (e.g. 10 → 100 → 200), matching how most fertility clinics report the ratio.
Also known as
TG we-Calculate Editorial Team. (2026). PG/E2 Ratio Calculator — Progesterone to Estradiol Ratio [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/pg-e2-ratio-calculator
TG we-Calculate Editorial Team. "PG/E2 Ratio Calculator — Progesterone to Estradiol Ratio." TG we-Calculate. 2026. https://we-calculate.com/calculator/pg-e2-ratio-calculator.
TG we-Calculate Editorial Team, "PG/E2 Ratio Calculator — Progesterone to Estradiol Ratio," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/pg-e2-ratio-calculator
@misc{wecalculate_pg_e2_ratio_calculator, title = {PG/E2 Ratio Calculator — Progesterone to Estradiol Ratio}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/pg-e2-ratio-calculator}}, year = {2026}, note = {TG we-Calculate} }
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