Hormone Balance Snapshot

Enter serum progesterone and estradiol results to evaluate the P/E2 ratio, useful for luteal support, fertility monitoring, or hormone therapy.

Progesterone value

Estradiol (E2) value

Cycle context

Progesterone (ng/mL)

12.00

Estradiol (pg/mL)

120

P/E2 ratio

100

Borderline balance: P/E2 ratio 100–199 may indicate borderline progesterone dominance; corroborate with absolute levels and clinical symptoms.

Mid-luteal progesterone (5–20 ng/mL) with adequate P/E2 ratio supports implantation. Consider timing 5–7 days post-ovulation.

How to Use This Calculator

Collect same-day serum labs

Ensure progesterone and estradiol are drawn on the same day, ideally during the target cycle phase (e.g., mid-luteal).

Select correct units

The tool converts between ng/mL ↔ nmol/L and pg/mL ↔ pmol/L so you can enter results as reported.

Interpret in clinical context

Use the ratio alongside absolute hormone levels, ovulation tracking, and symptoms to guide treatment decisions.

Formula

Progesterone (ng/mL) = Progesterone (nmol/L) × 0.314

Estradiol (pg/mL) = Estradiol (pmol/L) × 0.272

P/E2 ratio = (Progesterone (ng/mL) × 1000) ÷ Estradiol (pg/mL)

Ratios ≥200 are often cited for adequate luteal support; thresholds vary by clinic and indication.

Full Description

The progesterone-to-estradiol ratio provides insight into luteal phase sufficiency, hormone replacement balance, and overall reproductive hormone harmony. Elevated estradiol relative to progesterone may contribute to luteal phase defects, PMS, or estrogen-dominant symptoms. However, ratios should never be interpreted in isolation—cycle timing, absolute hormone levels, medication use, and clinical symptoms determine management. Consult fertility or endocrine specialists when adjusting progesterone supplementation or evaluating hormone therapy.

Frequently Asked Questions

When should I test for luteal adequacy?

Measure progesterone about 5–7 days after ovulation (mid-luteal). Confirm ovulation with LH surge or basal temperature.

Does supplementation change the ratio?

Yes. Progesterone therapy increases serum levels rapidly. Time blood draws relative to dosing for consistent interpretation.

Is there a universal optimal ratio?

No. Clinics use different cutoffs (often 200–300). Focus on clinical goals (fertility, hormone therapy, PMS relief).

Can estradiol be too low?

Yes. Extremely low estradiol may reflect anovulation or menopause. Evaluate in conjunction with FSH/LH and symptoms.