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. It is one marker among several, not a diagnosis on its own.
The ovarian volume 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
Reports often list the diameters in millimetres. Divide each by 10 before entering them: 32 × 24 × 20 mm becomes 3.2 × 2.4 × 2.0 cm.
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.
Ovarian volume 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.
Normal ovarian volume by age
Kelsey and colleagues pooled ultrasound measurements of almost 60,000 ovaries into a normative model of ovarian volume across life. Average volume rises through childhood, peaks at about 20 and falls steadily to menopause:
| Age | Mean volume |
|---|---|
| 2 years | 0.7 mL |
| 12 years | 3.7 mL |
| 14 years | 5.0 mL |
| 20 years (peak) | 7.7 mL |
| 30 years | 6.0 mL |
| 40 years | 5.4 mL |
| Menopause, about 50 | 2.8 mL |
These are averages, and healthy ovaries spread widely around them. Age alone explained 69% of the variation in the model, so a reading somewhat above or below the mean for your age is common.
Ovarian volume in current PCOS guidelines
The international evidence-based PCOS guideline (2018, updated in 2023) defines polycystic ovarian morphology on transvaginal ultrasound as either of these in at least one ovary:
- 20 or more follicles per ovary, counted with a transducer of 8 MHz or higher
- An ovarian volume of 10 mL or more, with no corpus luteum, cyst or dominant follicle present
Polycystic morphology is one of three diagnostic features, alongside irregular cycles and raised androgens, and a diagnosis needs two of the three. The guideline advises against ultrasound for diagnosis within 8 years of the first period, because many healthy adolescents have multi-follicular ovaries. In adults, the 2023 update accepts an AMH blood test in place of ultrasound.
Each ovary is judged on its own. Do not add the left and right volumes together: an 11 mL right ovary meets the volume criterion even when the left measures 6 mL.
The same method for other organs
The three-diameter ellipsoid method also measures the uterus, the prostate and the testis. The geometry stays the same and only the reference ranges change. The uterus volume calculator carries its own published centiles, and the ellipsoid volume calculator handles the general geometry.
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. Later criteria also count follicles, and a diagnosis always needs more than one measurement. Even so, 10 mL remains a widely used 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 has large cysts or an irregular shape. The formula multiplies three measurements, so small errors compound into a larger volume error.
Is an ovary volume calculator the same as an ovarian volume calculator?
Yes. Ovary volume and ovarian volume name the same measurement, and volume is the standard way to report ovary size. This ovary volume calculator applies the same ellipsoid formula either way: length × width × height × 0.523. Radiology reports normally say "ovarian volume", while patients more often search for "ovary volume".
Does ovarian volume change with age?
Yes. In a normative model built from almost 60,000 ovaries (Kelsey et al., 2013), mean volume rose from 0.7 mL at age 2 to a peak of 7.7 mL at 20, then fell to 6.0 mL at 30, 5.4 mL at 40 and 2.8 mL around menopause.
Should I add the left and right ovary volumes together?
No. Each ovary is measured and judged separately. The PCOS volume criterion of 10 mL or more applies to either ovary on its own, so an 11 mL right ovary meets it even if the left measures 6 mL.
Can I enter ovary measurements in millimetres?
Convert them first: divide each diameter by 10. A report reading 32 × 24 × 20 mm becomes 3.2 × 2.4 × 2.0 cm, which gives 15.36 × 0.523 = 8.03 mL.
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.
- Kelsey TW, Dodwell SK, Wilkinson AG, et al. Ovarian volume throughout life: a validated normative model. PLoS One 2013;8(9):e71465. doi:10.1371/journal.pone.0071465
- Teede HJ, Tay CT, Laven JJE, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. J Clin Endocrinol Metab 2023;108(10):2447–2469. doi:10.1210/clinem/dgad463
- Pea J, Bryan J, Wan C, et al. Ultrasonographic criteria in the diagnosis of polycystic ovary syndrome: a systematic review and diagnostic meta-analysis. Hum Reprod Update 2023;30(1):109–130. doi:10.1093/humupd/dmad027