Prostate Volume Calculator

Prostate volume is most commonly estimated using transrectal ultrasound (TRUS) or MRI. Radiologists measure three dimensions of the prostate (width, height, and length) and apply the ellipsoid formula: Volume = Width × Height × Length × 0.5236. This assumes the prostate is shaped like a three-dimensional ellipse (an ellipsoid).

Knowing the prostate's size is essential for diagnosing and managing Benign Prostatic Hyperplasia (BPH) and evaluating the significance of PSA (Prostate-Specific Antigen) levels. A larger prostate naturally produces more PSA. Estimating volume helps differentiate between benign enlargement and potential malignancy via PSA density.

A normal prostate volume for a young adult is about 20 to 25 cubic centimeters (cc or mL), roughly the size of a walnut. The prostate naturally enlarges as men age. In older individuals, a volume of 30 to 80 cc or more is common and is associated with Benign Prostatic Hyperplasia (BPH).

PSA density is calculated by dividing the serum PSA level (ng/mL) by the prostate volume (cc or mL). For example, if a patient has a PSA of 4.0 ng/mL and a prostate volume of 40 cc, the PSA density is 0.10 ng/mL/cc. It is a metric used to assess the likelihood of prostate cancer.

A PSA density value greater than 0.15 ng/mL/cc is generally considered elevated and is associated with a higher risk of prostate cancer, often prompting further diagnostic evaluation like an MRI or biopsy. A PSA density of 0.15 ng/mL/cc or less suggests that the elevated PSA is more likely due to benign enlargement (BPH).

Prostate tissue has a density of approximately 1.05 grams per milliliter (g/mL). Therefore, the weight of the prostate in grams is very close to its volume in cubic centimeters (V × 1.05). For clinical purposes, radiologists and urologists often use cc and grams interchangeably.