acalculator

What is my prostate volume?

Enter the three prostate measurements from an ultrasound or MRI report to calculate prostate volume by the ellipsoid formula, and add a PSA value for the PSA density. For information only. This is not medical advice or a diagnosis. Do not use it to make treatment decisions without a clinician. No licensed clinician has reviewed this page.

Your numbers

Units
Prostate volume
33

The prostate volume is 33 mL.

Prostate volume: 33. The prostate volume is 33 mL.

This calculator gives general information only. It is not medical advice and does not replace a doctor or other health care provider. Talk with a professional about your results. Terms of use

How to calculate

Calculates prostate volume from three ultrasound or MRI measurements with the ellipsoid formula (π/6 × length × width × height), and the PSA density when a PSA value is given.

Example with the default inputs (Length 4.5 cm, Width 3.5 cm, Height 4 cm): The prostate volume is 33 mL.

Method: Volume (mL) = π/6 × length × width × height, in cm. PSA density = PSA (ng/mL) ÷ volume (mL).

  • Measurements in centimeters (millimeters are divided by 10); 1 cm³ = 1 mL.
  • The volume is rounded to 1 decimal and the PSA density to 3 decimals, halves up; the density uses the unrounded volume.
  • The ellipsoid formula is an estimate. It is closest for glands under about 80 mL (Terris and Stamey 1991).

Machine-readable copies: Markdown, JSON.

Worked examples

Each example is checked against the calculator on every build.

  1. Length 4.5 cm, Width 3.5 cm, Height 4 cm, PSA (ng/mL) 5 gives Prostate volume 33, PSA density (ng/mL per mL) 0.152.Source: Π/6 × 4.5 × 3.5 × 4.0 = 32.987 mL (Terris and Stamey 1991, ellipsoid); 5 ÷ 32.987 = 0.1516 (Benson 1992)
  2. Length 5 cm, Width 4 cm, Height 4.5 cm, PSA (ng/mL) 3.2 gives Prostate volume 47.1, PSA density (ng/mL per mL) 0.068.
  3. Length 6 cm, Width 5.5 cm, Height 5 cm gives Prostate volume 86.4.
  4. Length 3 cm, Width 2.5 cm, Height 2.8 cm, PSA (ng/mL) 1.1 gives Prostate volume 11, PSA density (ng/mL per mL) 0.1.

Medical disclaimer

This calculator is for information and education only. It is not medical advice, and its result is not a diagnosis. Do not use it to start, stop, or change a treatment without a clinician who knows your health history. No licensed clinician has reviewed this page. This site's editors checked the formulas and worked examples against published sources. If you think you have a medical emergency, call your local emergency number.

When this does not apply. The ellipsoid formula estimates prostate volume from ultrasound or MRI measurements in adult men (Terris 1991); the result depends on how the gland was measured. Benson (1992) studied PSA density in men with prostate disease confined to the gland. PSA density does not diagnose cancer.

How the volume is worked out

Volume (mL) = π/6 × L × W × H

  • L is the length (head to foot), W the width (side to side), H the height (front to back), all in centimeters. Millimeters are divided by 10. 1 cm³ = 1 mL.
  • π/6 = 0.5235988 (the calculator uses π itself, not 0.52).
  • PSA density = PSA (ng/mL) ÷ volume (mL), with the unrounded volume.
  • The volume is rounded to 1 decimal place and the PSA density to 3, halves up, read from the decimal value (within 1e-9, relative, of a half counts as the half).
  • The PSA is optional. With no PSA, the page shows the volume only.

Inputs the calculator accepts

Each dimension 0.5 to 15 cm (5 to 150 mm). PSA 0 to 10,000 ng/mL.

Worked examples by hand

4.5 × 3.5 × 4.0 cm, PSA 5. 4.5 × 3.5 × 4.0 = 63; 63 × 0.5235988 = 32.987 = 33.0 mL. PSA density: 5 ÷ 32.987 = 0.152.

5.0 × 4.0 × 4.5 cm, PSA 3.2. 90 × 0.5235988 = 47.124 = 47.1 mL. PSA density: 3.2 ÷ 47.124 = 0.068.

6.0 × 5.5 × 5.0 cm. 165 × 0.5235988 = 86.394 = 86.4 mL.

30 × 25 × 28 mm, PSA 1.1. 3.0 × 2.5 × 2.8 = 21; × 0.5235988 = 10.996 = 11.0 mL. PSA density: 1.1 ÷ 10.996 = 0.100.

Other questions people ask

How is prostate volume calculated?

With the ellipsoid (prolate spheroid) formula: volume = π/6 × length × width × height. π/6 is about 0.52, so the formula is often written as length × width × height × 0.52. With the measurements in centimeters, the result is in milliliters (1 cm³ = 1 mL).

What is a normal prostate volume?

A young adult prostate is about 20 to 25 mL. It often grows with age (benign prostatic hyperplasia). Your radiologist or urologist reads the size in the context of your age and symptoms.

What is PSA density?

PSA density (PSAD) is the PSA level in ng/mL divided by the prostate volume in mL. Benson and others (1992) proposed it because a large benign gland makes more PSA, so the same PSA means less in a large gland than in a small one.

How accurate is the ellipsoid formula?

Terris and Stamey (1991) compared ultrasound volume methods with the weight of the removed gland. The ellipsoid volume correlated well (r = 0.90). All ultrasound estimates depend on how the gland is measured.