How to read this calculator
Enter the measurements, or press Simulate to load a case from the reviewed validation catalog. The calculator then shows:
- Results: Prostate volume and PSA density as plain numbers, with no interpretation attached.
- PSA-density bands: This describes the PSA-density band, not an individual cancer probability. Interpretation also requires MRI and clinical context.
Decision steps
Radikulus assigns an exact boundary value to the higher band. The source table does not define every equality boundary.
| Step | Criterion | Meaning |
|---|---|---|
| P1 | Under 0.10 | Low PSAD |
| P2 | 0.10 to under 0.15 | Intermediate-low PSAD |
| P3 | 0.15 to under 0.20 | Intermediate-high PSAD |
| P4 | 0.20 or higher | High PSAD |
How prostate volume is measured
PI-RADS v2.1 states that prostate volume should always be reported in prostate MRI reports. It may be determined by segmentation or with the ellipsoid formula: maximum anteroposterior dimension × maximum longitudinal dimension (both on the mid-sagittal T2-weighted image) × maximum transverse dimension (on the axial T2-weighted image) × 0.52.
Prostate volume depends on measurement method. EAU reports a series of 640 men in which TRUS volumes averaged 8% smaller than MRI, and separately cites transabdominal ultrasound overestimation of 9.9 mL. These study findings are not correction factors for an individual measurement.
Interpretation and limitations
EAU 2026 Table 5.5 combines PSA-density categories with PI-RADS findings in biopsy-naïve men with suspected prostate cancer, drawing on Schoots and Padhani’s 2021 analysis. Its source labels are <0.10, 0.10–0.15, 0.15–0.20 and >0.20 ng/mL/mL; Radikulus explicitly assigns exact boundaries to the higher band. EAU’s weak recommendations allow biopsy omission with PSA monitoring after negative MRI and low clinical suspicion, including PSAD <0.20 and no family history, or after PI-RADS 3 MRI and very low clinical suspicion, including PSAD <0.10 and no family history. These clinical decisions require the full guideline and are not generated by this calculator.
PSA density can also inform risk assessment before MRI; this calculator does not determine whether MRI is indicated.
PSA can rise with prostatitis, urinary infection and urinary retention. Finasteride and dutasteride lower PSA and also affect gland volume; this calculator applies no medication correction. Timing and clinical context remain necessary.
Reference observations
In 1,037 men from a Northern German population cohort without documented prostate cancer, BPH or lower urinary tract symptoms at baseline or during approximately 10 years of follow-up, segmented MRI prostate volume had a median of 31.3 mL and 5th–95th percentiles of 20.7–51.4 mL; median PSAD was 0.025 ng/mL/mL. These are cohort reference values, not universal normal limits for an ellipsoid estimate. Volume varied with age and BMI, and agreement between ellipsoid and segmented volumes was imperfect (Lindholz 2026).
In Benson’s 1992 series of 61 men, mean PSAD was 0.581 in 41 cancer patients and 0.044 in 20 patients with BPH. Volumes used a 0.5 coefficient, with MRI measurements for BPH and surgical-specimen dimensions for cancer.
In a population-based study of 5,291 men with PSA of 3 ng/mL or higher (STHLM3), the median PSAD was 0.10 ng/mL/mL. PSAD cutoffs of 0.10 and 0.15 ng/mL/mL detected 77% and 49% of Gleason score 7 or higher cancers, respectively.
Bazinet’s 1994 referral cohort identified a 0.15 PSAD cutoff in 142 men with PSA 4.1–10 ng/mL and no cancer suspicion on DRE or TRUS. This was a population-specific finding, not a universal cutoff.
Published report example
Published example, not a patient: PI-RADS v2.1’s sample report gives dimensions 4.0 × 4.0 × 5.0 cm and PSA 12.1 ng/mL. Using 0.52 gives volume 41.60 mL and PSAD 0.2909 ng/mL/mL; the report states 42 mL and 0.29.
Worked example
Published case — chronic prostatitis on biopsy, with regression after treatment despite PI-RADS 5 MRI findings. MRI dimensions and PSA from Ozdemir 2026, Case presentation. PSA-density band alone does not establish the diagnosis. PUB-03; PMID 42192391.
| Item | Value |
|---|---|
| Anteroposterior (AP) | 52 mm |
| Longitudinal (craniocaudal) | 36 mm |
| Transverse | 53 mm |
| Serum total PSA (ng/mL, optional) | 2.7 |
| Prostate volume | 51.59 mL |
| PSA density | 0.052 ng/mL/mL |
This value falls in the Low PSAD band displayed here from EAU 2026 Table 5.5.
EAU’s reference table studied biopsy-naïve men with suspected prostate cancer. These bands alone do not estimate an individual’s cancer risk; interpretation also requires MRI and clinical context. Interpretation and limitations
Frequently asked questions
How is prostate volume calculated?
AP × longitudinal × transverse × 0.52, with dimensions in cm (PI-RADS v2.1).
How do you calculate PSA density?
PSA density = serum total PSA ÷ prostate volume.
How are PSA-density bands assigned?
This calculator displays four bands adapted from EAU 2026 Table 5.5: under 0.10, 0.10 to under 0.15, 0.15 to under 0.20, and 0.20 or higher ng/mL/mL. Assigning exact boundary values to the higher band is Radikulus’s convention. These bands alone do not determine cancer risk or biopsy decisions.
What is a normal prostate volume?
There is no single normal prostate volume. In 1,037 men from a Northern German population cohort without documented prostate cancer, BPH or lower urinary tract symptoms, segmented MRI prostate volume had a median of 31.3 mL and 5th–95th percentiles of 20.7–51.4 mL. These are cohort reference values, not universal normal limits for an ellipsoid estimate; volume varied with age and BMI (Lindholz 2026).
What is a normal PSA density?
There is no single normal PSA density. EAU 2026 Table 5.5 combines PSA density with PI-RADS findings in biopsy-naïve men with suspected prostate cancer. This calculator’s bands are adapted from that table; assigning exact boundary values to the higher band is Radikulus’s convention. PSA density alone does not determine cancer risk or biopsy decisions.
References
- American College of Radiology. PI-RADS: Prostate Imaging – Reporting and Data System, version 2.1 (2019). https://www.acr.org/Clinical-Resources/Clinical-Tools-and-Reference/Reporting-and-Data-Systems/PI-RADS ; and Turkbey B, Rosenkrantz AB, Haider MA, et al. Prostate Imaging Reporting and Data System Version 2.1: 2019 update of Prostate Imaging Reporting and Data System Version 2. Eur Urol. 2019;76(3):340-351. doi:10.1016/j.eururo.2019.02.033. PMID 30898406.
- Benson MC, Whang IS, Pantuck A, et al. Prostate specific antigen density: a means of distinguishing benign prostatic hypertrophy and prostate cancer. J Urol. 1992;147(3 Pt 2):815-816. doi:10.1016/s0022-5347(17)37393-7. PMID 1371554.
- Nordström T, Akre O, Aly M, Grönberg H, Eklund M. Prostate-specific antigen (PSA) density in the diagnostic algorithm of prostate cancer. Prostate Cancer Prostatic Dis. 2018;21(1):57-63. doi:10.1038/s41391-017-0024-7. PMID 29259293.
- EAU Guidelines on Prostate Cancer 2026, Table 5.5. https://uroweb.org/guidelines/prostatecancer/chapter/diagnostic-evaluation
- Schoots and Padhani. BJU Int 2021;127:175–178. doi:10.1111/bju.15277. PMID 33089586.
- Lindholz et al. Eur Radiol 2026. doi:10.1007/s00330-026-12937-2. PMID 42789055.
- Bazinet et al. Urology 1994;43:44–51. doi:10.1016/s0090-4295(94)80260-2. PMID 7506853.