Educational tool — not a diagnosis. This applies a published formula to numbers you enter. Ovarian volume is interpreted by clinicians alongside the menstrual cycle stage, follicle count, symptoms and other findings.
Discuss any result with the healthcare professional who arranged your scan. A single volume does not diagnose or exclude any condition.
Quick answer: volume = length × width × height × 0.523, with diameters in centimetres. A 3 × 2 × 2 cm ovary is about 6.28 mL. The Rotterdam criteria cite an ovary above 10 mL as one ultrasound marker of polycystic morphology — one marker among several, not a diagnosis on its own.
The formula
The ovary is modelled as a prolate ellipsoid, and the coefficient is π/6 — the same pure-geometry value used for the prostate, rounded here to 0.523. Worked example — an ovary measuring 3.2 × 2.4 × 2.0 cm:
- Multiply the diameters: 3.2 × 2.4 × 2.0 = 15.36
- Apply the coefficient: 15.36 × 0.523 = 8.03 mL
The ellipsoid (π/6) method is standard for ovarian volume estimation on ultrasound. The Rotterdam ESHRE/ASRM consensus (2003) used an ovarian volume > 10 mL as one criterion for polycystic ovarian morphology.
Reference figures
| Group | Commonly cited volume |
|---|---|
| Reproductive age | ≈ 3–10 mL (varies through the cycle) |
| Postmenopausal | Typically under ~3 mL |
| Rotterdam PCOS marker | > 10 mL per ovary |
Ovarian volume changes naturally across the menstrual cycle as follicles grow, and it declines after menopause. These figures are general orientation; the meaningful interpretation always depends on cycle timing, symptoms and the full clinical assessment.
Estimating uterine or other volumes
The same three-diameter ellipsoid method estimates uterine volume, and volumes of other roughly ellipsoidal structures such as testicular volume. Just enter the three perpendicular diameters — the geometry is identical, only the reference ranges differ. The ellipsoid volume calculator is the general-purpose version.
Frequently asked questions
How is ovarian volume calculated?
With the ellipsoid formula: volume = length × width × height × 0.523, using three perpendicular diameters in centimetres. An ovary measuring 3 × 2 × 2 cm gives 12 × 0.523 ≈ 6.28 cm³. Because 1 cm³ equals 1 mL, the result is in millilitres.
What is a normal ovarian volume?
In women of reproductive age, ovarian volume is commonly cited as around 3 to 10 mL, varying through the menstrual cycle as follicles develop. Volume declines after menopause to typically under about 3 mL. These are general figures and ranges differ between sources.
What is the Rotterdam PCOS threshold?
The 2003 Rotterdam criteria used an ovarian volume above 10 mL as one ultrasound marker of polycystic ovarian morphology. Diagnostic criteria have since been refined and also consider follicle number, and a diagnosis requires more than a single measurement — but 10 mL remains a widely referenced volume threshold.
Why is 0.523 used instead of 0.52?
Both are roundings of π/6 = 0.5236, the exact coefficient for a prolate ellipsoid in terms of its three full diameters. Different sources round to 0.52 or 0.523; the difference is negligible, well under one percent.
How accurate is ultrasound ovarian volume?
It is a reasonable estimate for a normally shaped ovary. Accuracy falls when the ovary contains large cysts or is irregular, and because three measurements are multiplied, small measurement errors compound into a larger volume error.
References
- Prolate ellipsoid volume formula — standard geometric derivation, V = (π/6) × d₁ × d₂ × d₃.
- Rotterdam ESHRE/ASRM-Sponsored PCOS Consensus Workshop Group. Revised 2003 consensus on diagnostic criteria for polycystic ovary syndrome. Human Reproduction / Fertility and Sterility, 2004.
- General references on ovarian volume reference ranges across reproductive life.