Calculate progesterone, estradiol, or Pg/E2 ratio from any 2 values with ng/mL, nmol/L, pg/mL, or pmol/L unit conversions and steps.
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Pg/E2 Ratio Formula
The Pg/E2 ratio compares progesterone to estradiol after converting both values to compatible base units. This calculator uses progesterone in ng/mL and estradiol in pg/mL.
Pg/E2 = (Pg * 1000) / E2
Pg = (Pg/E2 * E2) / 1000
E2 = (Pg * 1000) / Pg/E2
- Pg/E2 = progesterone to estradiol ratio, unitless
- Pg = progesterone, in ng/mL after conversion
- E2 = estradiol, in pg/mL after conversion
- 1000 = conversion factor from ng to pg
The ratio is unitless because progesterone is converted from ng/mL to pg/mL before dividing by estradiol. Estradiol cannot be zero when calculating the ratio. The ratio cannot be zero when solving for estradiol.
Pg and E2 Unit Conversions
Use these conversions when comparing lab results reported in different units.
| Measurement | From | To base unit |
|---|---|---|
| Progesterone | ng/mL | multiply by 1 |
| Progesterone | nmol/L | multiply by 0.314465 to get ng/mL |
| Estradiol | pg/mL | multiply by 1 |
| Estradiol | pmol/L | multiply by 0.272405 to get pg/mL |
Reading a Pg/E2 Ratio Result
| Result factor | Why it matters |
|---|---|
| Cycle timing | Progesterone and estradiol change across the menstrual cycle, so timing affects the ratio. |
| Unit consistency | The formula assumes Pg is in ng/mL and E2 is in pg/mL before the ratio is calculated. |
| Lab method | Different labs and test methods can produce slightly different hormone values. |
Quick Example
If your progesterone is 15 ng/mL and your estradiol is 150 pg/mL, the calculation is:
Pg/E2 = (15 * 1000) / 150 = 100
The Pg/E2 ratio is 100. Use the result as a calculation aid, not as a diagnosis. Lab results should be interpreted with symptoms, cycle timing, medications, and clinical context.
