PSA Density Calculator

Divide serum PSA by prostate volume (from length x width x height x 0.52) to get PSA density in ng/mL per cc.

Quick Facts

Formula
PSAD = PSA / (L x W x H x 0.52)
Prostate volume uses the ellipsoid (prolate spheroid) approximation from ultrasound or MRI measurements.
Common threshold
0.15 ng/mL/cc
A frequently cited cut-point above which further evaluation is often considered, most relevant when PSA is 4-10 ng/mL.

Your Results

Calculated
PSA density
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ng/mL per cc
Prostate volume
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Ellipsoid formula (mL)
Serum PSA used
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As entered (ng/mL)
Density category
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Vs. common 0.10 / 0.15 cut-points

Ready

Enter PSA and the three prostate dimensions, then calculate.

About PSA density

PSA density (PSAD) adjusts a man's serum PSA level for the size of his prostate. Because benign prostatic hyperplasia (BPH) causes the prostate to produce more PSA even without cancer, a raised total PSA can simply reflect a larger gland. Dividing PSA by prostate volume gives a value that is less influenced by gland size, which is why PSAD is used most often to help interpret PSA results that fall in the 4 to 10 ng/mL "gray zone."

How the calculation works

  • Prostate volume is estimated from three ultrasound or MRI measurements using the ellipsoid (prolate spheroid) formula: volume (mL) = length x width x height x 0.52, with each dimension in centimeters.
  • PSA density is then serum PSA (ng/mL) divided by that volume (mL), reported in ng/mL per cc.
  • Both the PSA level and the prostate dimensions should come from the same clinical workup, since volume and PSA can each change over time.

Putting the result in context

A PSA density under about 0.10 ng/mL/cc is generally associated with a lower probability of clinically significant prostate cancer, 0.10 to 0.15 falls in an intermediate zone, and 0.15 ng/mL/cc or higher is a commonly cited threshold for considering further evaluation such as MRI or biopsy. These are reference cut-points drawn from the urology literature, not a diagnosis — they are typically weighed alongside PSA velocity, free-to-total PSA ratio, imaging findings, and digital rectal exam results.

When to consult a professional

This calculator performs the standard PSA density arithmetic; it does not diagnose prostate cancer or recommend a course of action. Interpret any PSA density result together with a urologist, who can weigh it against your full history, imaging, and other PSA-derived measures before deciding on next steps such as active surveillance, biopsy, or repeat testing.

Frequently Asked Questions

What is PSA density and how is it calculated?
PSA density (PSAD) is serum PSA divided by prostate volume: PSAD = PSA (ng/mL) / prostate volume (mL). Prostate volume is usually measured on ultrasound or MRI and approximated with the ellipsoid formula: volume = length x width x height x 0.52, with all three dimensions in centimeters. The result is expressed in ng/mL per cc.
What PSA density value is considered elevated?
Commonly cited thresholds treat a PSA density under 0.10 ng/mL/cc as lower probability of clinically significant prostate cancer, 0.10 to 0.15 as an intermediate zone, and 0.15 ng/mL/cc or higher as an elevated result often used to prompt further evaluation such as MRI or biopsy. These are reference cut-points from the urology literature, not a diagnosis.
Why use PSA density instead of PSA alone?
Total PSA rises with prostate size even without cancer, since benign prostatic hyperplasia (BPH) also produces PSA. Dividing PSA by prostate volume adjusts for that, so two men with the same PSA but different gland sizes can have different PSA density values. It is most often used for PSA values in the 4 to 10 ng/mL gray zone and for monitoring during active surveillance.

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