Calculate prostate volume by the ellipsoid formula from ultrasound dimensions, with PSA density when PSA is entered.
Result
How to use this tool
Enter the three ultrasound dimensions in cm.
Optionally add PSA for the density.
Read the volume, size band and density.
Discuss any enlargement or raised density with the treating clinician.
Formula & worked example
Dimensions of 5 x 4 x 4 cm give pi / 6 x 80 = 41.89 mL, mildly enlarged.
Limitations — read this before you rely on it
Volume estimate from three diameters; irregular glands reduce accuracy. PSA density thresholds vary by guideline and never decide a biopsy alone. This tool is for education only and is not medical advice. Talk to a clinician about any result that worries you, and never change treatment because of a calculator result.
Frequently asked questions
Pi divided by 6, times length times width times height — the standard ultrasound volume estimate.
Roughly 20-30 mL in younger men, rising with age; above 30 mL is commonly called enlarged.
PSA divided by prostate volume. Above about 0.15 ng/mL per mL is often flagged in biopsy decisions.
No. Benign enlargement is common, and small prostates can harbour cancer — size is one piece of the picture.
The three largest diameters on transrectal or transabdominal ultrasound, in centimetres.