Ovarian Reserve Index (ORPI) Calculator

Use this calculator to estimate an ovarian response prediction index (often called ORPI) from AMH, antral follicle count (AFC), and age to get a simple IVF stimulation response category. It estimates expected egg yield response, not your chance of pregnancy.

Age (years)

AMH value (ng/mL or pmol/L)

AMH unit

Antral follicle count (AFC, total both ovaries)

Advanced options

Interpretation settings

Cutoff set for interpretation

AFC measurement note

Timing

Age at test date (optional) (years)

Ovarian reserve/response index (ORPI = AMH x AFC / age)

N/A

Higher usually means more eggs expected in a stimulation cycle; lower usually means fewer eggs expected. This does not predict whether you will get pregnant.

AMH used in calculation (ng/mL)

N/A

Use this to double-check you picked the right AMH unit.

Likely ovarian response category (for IVF stimulation)

N/A

Based on the cutoff set you chose. Categories are study-based labels, not a diagnosis. If you are not doing IVF, this category may not be meaningful.

Poor response threshold check

N/A

Below-threshold suggests higher chance of few eggs retrieved, not zero chance.

High response threshold check

N/A

Above-threshold can suggest higher chance of high egg yield and may be relevant to OHSS risk planning with your clinic.

Input warnings (possible mistakes or out-of-range values)

None

Warnings do not change your calculated index.

Reminder: AMH and AFC are ovarian reserve markers (how many follicles you might be able to recruit). Age is strongly tied to egg quality. ORPI is mainly used to estimate ovarian response in IVF, not pregnancy chances.

How to use our Ovarian Reserve Index (ORPI) Calculator

Enter your Age (years). If your lab and ultrasound were done in the past, you can use the optional Age at test date in Advanced options.
Enter your AMH value exactly as shown on your lab report.
Select the AMH unit (ng/mL or pmol/L) to avoid a wrong conversion.
Enter your Antral follicle count (AFC) as the total from both ovaries (not per ovary).
Open Advanced options and pick a Cutoff set if you want a specific study-based interpretation label.
In Advanced options, choose the AFC measurement note that best matches how your clinic counted follicles (size ranges can differ).
Click Calculate.
Read the ORPI number and the response category. Then check the two threshold lines (poor and high response checks).
Review Input warnings and fix any possible mistakes (wrong AMH unit, AFC per-ovary, or age outside common study ranges), then recalculate.

Definitions

Ovarian reserve: A general term for how many eggs you might still have and how your ovaries may respond to stimulation; it is not the same as egg quality.

AMH (anti-Mullerian hormone): A hormone made by small growing follicles. Higher AMH often means more follicles available to respond to IVF stimulation, but lab methods and units vary.[3]

AFC (antral follicle count): The number of small follicles seen on ultrasound, usually early in the menstrual cycle. Reports may use different follicle size ranges.[3]

ORPI (ovarian response prediction index): An index that combines AMH, AFC, and age to estimate likely ovarian response (expected egg yield) during IVF stimulation.[2]

Poor vs normal vs high response: Study-based labels describing likely low, typical, or high egg yield in an IVF stimulation cycle; they do not guarantee outcomes.

Methodology

What this calculator computes

This tool computes the ovarian response prediction index (ORPI), also called an ovarian reserve/response index by some sites. ORPI is used in research and IVF settings to estimate how strongly the ovaries may respond to stimulation (how many eggs might be retrieved), not whether pregnancy will happen.[2]

Inputs and unit handling

AMH can be reported in ng/mL or pmol/L. To keep the formula consistent, the calculator converts AMH to ng/mL when you select pmol/L using: AMH (ng/mL) = AMH (pmol/L) / 7.14. The factor 7.14 is a commonly used AMH unit conversion (1 ng/mL = 7.14 pmol/L).

ORPI formula

The index is calculated as: ORPI = (AMH in ng/mL x total AFC) / age in years.[2] If you enter Age at test date (optional), that age is used in the denominator instead of your current age to better match the timing of the AMH/AFC measurements.

Response category and threshold checks

After ORPI is calculated, the tool labels response category using the selected cutoff set: if ORPI is at or below the poor-response cutoff, it reports likely poor response; if ORPI is at or above the high-response cutoff, it reports likely high response; otherwise it reports likely normal response. One published set uses example cutoffs near 0.12 for poor response and 0.42 for excessive response; different studies may use different thresholds and outcomes.[1]

Input warnings (do not change the math)

The calculator also shows non-blocking warnings to help prevent common mistakes: possible AMH unit mismatch (for example, selecting pmol/L but typing a value that looks like typical ng/mL ranges), AFC entered per ovary instead of total, AFC = 0 (unusual, confirm the report), and ages outside common IVF study ranges where cutoffs may not apply. Warnings do not change the ORPI number; they are prompts to re-check your reports.

Limits of interpretation

AMH and AFC are useful markers for predicting ovarian response to stimulation, but they are not direct measures of egg quality and do not guarantee pregnancy or live birth.[3][4] Use results as a discussion aid with your fertility clinic.