Progesterone to Estrogen Ratio Calculator · Pg/E2

Progesterone to Estrogen Ratio Calculator

Enter your progesterone and estradiol lab values in any unit to calculate your Pg/E2 ratio

Your lab values

Progesterone

Estradiol

Ratio (Pg/E2 or P/E2)

Formula: Pg/E2 = progesterone (normalised to ng/mL) ÷ estradiol (normalised to pg/mL). Optimal ratio is 100–500 when both hormones are within their normal luteal phase ranges. Units are converted automatically.

Quick examples

Your Pg/E2 Ratio

Progesterone to estrogen ratio

— :1

— 100–500 optimal Pg ÷ E2

Progesterone

—

Estradiol

—

Pg/E2 ratio

—

Balance

—

Where your ratio falls on the 0–600 scale

Estrogen dominance
< 100 Optimal
100 – 500 Progesterone dominance
> 500

Ratio interpretation

Pg/E2 ratio	Interpretation	Typical meaning

Unit conversion reference

Hormone	From	To	Multiply by

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Creator & Maintainer

Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.

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Introduction

Two labs, two sets of units. One reports progesterone in ng/mL, the other in nmol/L. One uses pg/mL for estradiol, the other pmol/L. Before you can divide one by the other, they need to be in the same reference frame. That’s the part this calculator handles.

The formula itself is simple. Progesterone in ng/mL divided by estradiol in pg/mL gives the Pg/E2 ratio. The complexity is in the unit conversions, and there are more of them than most people expect. Progesterone alone has five common units in clinical use, and estradiol has four. Mixing them up produces a number that’s off by a factor of a thousand or more.

How to Use the Pg/E2 Ratio Calculator

Enter your progesterone value in the first field.
Pick the matching unit from the dropdown: ng/mL, nmol/L, pg/mL, ng/dL, or µg/L.
Enter your estradiol value in the second field.
Choose the estradiol unit: pg/mL, pmol/L, ng/L, or ng/mL.
Watch the ratio field. It updates automatically as you type.
Read the hero panel. The Pg/E2 ratio appears with the balance category below it.
Check the four tiles for the raw progesterone, raw estradiol, the ratio, and the balance label.
Follow the gauge to see where the ratio falls against the optimal 100–500 band.

How the Pg/E2 Ratio Calculator Formula Works

Formula: Pg/E2 ratio = progesterone (ng/mL) ÷ estradiol (pg/mL)

Both hormones are normalised to the reference units before dividing. Progesterone converts to ng/mL through one of these factors:

ng/mL: no change
nmol/L: divide by 3.18
pg/mL: divide by 1,000
ng/dL: divide by 100
µg/L: no change (1 µg/L equals 1 ng/mL)

Estradiol converts to pg/mL through one of these:

pg/mL: no change
pmol/L: divide by 3.67
ng/L: no change (1 ng/L equals 1 pg/mL)
ng/mL: multiply by 1,000

Once the ratio is calculated, the tool classifies it. Below 100 suggests estrogen dominance. Between 100 and 500 is considered balanced. Above 500 suggests progesterone dominance. The gauge displays the ratio on a 0–600 scale, with the optimal band marked in green.

Ratio values are formatted as whole numbers. Extreme inputs (very high estradiol, very low progesterone) can push the ratio below 1, which still displays but lands outside the meaningful range.

Worked Example

Suppose your lab reports progesterone as 42 nmol/L and estradiol as 380 pmol/L. Neither value is in the reference unit yet.

Progesterone: 42 nmol/L ÷ 3.18 = 13.2 ng/mL
Estradiol: 380 pmol/L ÷ 3.67 = 103.5 pg/mL
Pg/E2 ratio = 13.2 ÷ 103.5 = 0.128, rounded to 0
Interpretation: below the optimal range

That output looks broken, and it is — because 42 nmol/L is a normal progesterone value but 380 pmol/L is on the high side for estradiol outside the ovulatory window. The ratio comes out under 1, which is far below the optimal band. The gauge would push the marker to the far left.

A more balanced input: progesterone at 15 ng/mL and estradiol at 150 pg/mL. That produces a ratio of 100, which sits at the bottom edge of the optimal range. A progesterone of 22 ng/mL with the same estradiol gives 147, comfortably inside. This is the range most mid-luteal samples land in when the sample was collected at the right time.

Frequently Asked Questions

What does the Pg/E2 ratio measure?

It measures the balance between progesterone and estradiol, not the absolute level of either. It’s calculated by dividing progesterone in ng/mL by estradiol in pg/mL. Optimal range for a mid-luteal sample is 100 to 500.

How do you calculate the Pg/E2 ratio?

Convert progesterone to ng/mL and estradiol to pg/mL, then divide the first by the second. A progesterone of 15 ng/mL and estradiol of 150 pg/mL produce a ratio of 100.

Why does unit choice matter for the ratio?

Because dividing values in mismatched units produces a number that’s off by a factor of a thousand or more. Progesterone in nmol/L and estradiol in pg/mL can’t be divided directly. Both need to be normalised first.

What is the optimal Pg/E2 ratio range?

100 to 500 for a mid-luteal sample. Below 100 suggests estrogen dominance. Above 500 suggests progesterone dominance, usually from supplementation. Some practitioners narrow the optimal band to 100–200.

What does a low Pg/E2 ratio mean?

It means progesterone is low relative to estradiol. Symptoms can include breast tenderness, fluid retention, hip and thigh weight gain, anxiety, and heavy periods. Whether treatment is needed depends on the full clinical picture.

What does a high Pg/E2 ratio mean?

It means progesterone is high relative to estradiol, most commonly from progesterone supplementation. Symptoms mimic estrogen deficiency: low mood, fatigue, sleep issues, bloating, and headaches.

Can you use the ratio in the follicular phase?

The number still calculates, but it isn’t clinically meaningful in that window. Progesterone is naturally low before ovulation, so the ratio will look artificially skewed toward estrogen.

When is the best time to test?

Mid-luteal phase, roughly seven days after confirmed ovulation. In a 28-day cycle, that’s around day 21. Testing at any other time produces a ratio that can’t be compared to the standard reference range.

Does the ratio apply to men or postmenopausal women?

The 100–500 range is based on cycling women. Men have different reference values, and postmenopausal women typically have low levels of both hormones. The ratio still calculates but needs different reference points.

What if one hormone is normal and the other isn’t?

The ratio can still land inside the optimal band even when one hormone is out of range. That’s why the ratio should be read alongside each individual value, not in isolation.

Do home hormone tests give the same result as serum?

Not always. Saliva measures free hormone, which doesn’t always track serum levels. Dried blood spots can have variable absorption. Serum testing drawn at the correct cycle day is the clinical standard.

Should you make treatment decisions based on the ratio alone?

No. The ratio is one data point. Clinical decisions depend on symptoms, history, cycle timing, and often a repeat measurement. Always discuss results with a healthcare provider before changing any treatment.

Disclaimer

This Pg/E2 ratio calculator is for educational purposes only and is not medical advice. It applies standard unit conversions and published reference ranges to the values you enter. The ratio is only clinically interpretable from a mid-luteal phase sample, and even then it should be read alongside symptoms, medical history, and other lab findings. Reference ranges vary by laboratory and practitioner. Always discuss your results with a healthcare provider before making any decisions about testing, supplementation, or treatment.