PSA Prostate Volume Ratio Calculator

Case	Total PSA (ng/mL)	Volume (mL)	Ratio	Example Note
Case A	3.2	38	0.0842	Below the common 0.10 reference level.
Case B	5.6	40	0.1400	Between the two example thresholds.
Case C	7.8	42	0.1857	Above the example high threshold.
Case D	4.9	31.20	0.1571	Volume can also come from dimensions.

Formula Used

Primary ratio formula: PSA Volume Ratio = Total PSA ÷ Prostate Volume

Dimension-based volume formula: Prostate Volume = Length × Width × Height × Ellipsoid Coefficient

Total PSA is commonly entered in ng/mL. Prostate volume is commonly entered in mL. Because 1 cm³ is approximately 1 mL, dimension-based volume can directly support the same ratio calculation.

This page also compares the result with two user-adjustable thresholds, helping you review a lower, borderline, or higher range quickly.

How to Use This Calculator

Choose direct volume or dimension-based volume entry.
Enter the total PSA value.
Enter known prostate volume, or enter dimensions.
Keep the ellipsoid coefficient at 0.52 unless needed.
Optionally enter free PSA and age.
Set your review thresholds and preferred precision.
Press Calculate Ratio to see results above the form.
Use the CSV and PDF buttons to save the result.

FAQs

1) What does this calculator measure?

It measures the ratio between total PSA and prostate volume. Many clinicians call this PSA density. The value helps place PSA in the context of gland size.

2) Why can I enter dimensions instead of volume?

Some reports list gland measurements rather than final volume. This tool estimates volume from length, width, height, and an ellipsoid coefficient.

3) What is the usual coefficient for prostate volume?

A coefficient of 0.52 is commonly used for ellipsoid volume estimation. Leave it unchanged unless your imaging method uses a different value.

4) Does a higher ratio confirm disease?

No. A higher ratio does not confirm disease. It is only one review point and should be interpreted with symptoms, imaging, labs, and clinical judgment.

5) Why are there threshold fields?

Different clinics may review different cutoffs. Adjustable thresholds let you compare one result against your preferred reference ranges.

6) What happens if I enter free PSA?

The page also calculates free PSA percentage. That extra value can help you review a broader screening picture, though it does not change the main ratio.

7) Are the exports useful for record keeping?

Yes. The CSV export is useful for spreadsheets. The PDF export is useful for reports, reviews, or saving a quick snapshot of the calculation.

8) Is this page a diagnosis tool?

No. This calculator is for educational and review purposes only. Medical decisions should always come from a qualified clinician who knows the full case.