Prostate health index (phi) calculator
A calculated score that combines total PSA, free PSA and p2PSA to estimate how likely a biopsy is to find prostate cancer when total PSA is mildly raised. Type your results in the units on your report and it works out phi as you type, in your browser.
AI-verified against cited sources. Awaiting expert reviewLast reviewed 2026-10-03Cancer Markers
Type your results above, or fill in the example, to see phi.
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Educational information, not medical advice. Blood Test Tracker doesn’t diagnose or treat, and it doesn’t replace your clinician. Talk with your clinician before changing medications, supplements or care.
How it’s worked out
The formula
phi = (p2PSA ÷ free PSA) × √(total PSA), with p2PSA in pg/mL and free PSA and total PSA in ng/mL. All three values come from the same blood sample, measured on Beckman Access assays.
A worked example
Example numbers, not anyone’s real results, run through the same code as the calculator above.
| p2PSA ([-2]proPSA) | 15 pg/mL |
|---|---|
| Free PSA | 1 ng/mL |
| PSA | 5 ng/mL |
| phi | 33.5 phi score |
What phi tells you
The Prostate Health Index (phi) is a score the lab calculates, not a separate blood test. From one blood sample, the lab measures total PSA, free PSA and a form of PSA called p2PSA (also written [-2]proPSA). It puts the three numbers into a formula, and a higher score goes with a higher chance that a biopsy will find prostate cancer. The score is meant for men 50 and older whose total PSA is between 4.0 and 10.0 ng/mL and whose rectal exam did not look suspicious. Mayo does not report it outside that PSA range.
A mildly raised PSA has many possible causes, and most are not cancer. In this middle range, a biopsy often finds nothing. phi is one of several add-on tools, along with percent free PSA, other blood or urine tests and MRI, that can help you and your clinician decide whether to go further. In Mayo's table, cancer was found in about 10 of 100 men with a score under 27 and in about 50 of 100 men with a score of 55 or higher. The AUA guideline says clinicians may use add-on tests like this when the extra information would change the decision about a biopsy. That is a conditional recommendation based on limited evidence. phi does not diagnose cancer.
Read the full page on phi, with what a high or low result can mean.
Sources
The equation
- A multicenter study of [-2]pro-prostate specific antigen combined with prostate specific antigen and free prostate specific antigen for prostate cancer detection in the 2.0 to 10.0 ng/ml prostate specific antigen range, The Journal of Urology (2011)
- P2PHI - Overview: [-2]Pro Prostate Specific Antigen with Prostate Health Index, Serum, Mayo Clinic Laboratories
3 more sources for the ranges and the explanation
- PHI11 - Overview: Prostate Health Index Reflex, Serum, Mayo Clinic Laboratories
- The Prostate Health Index: a new test for the detection of prostate cancer, Therapeutic Advances in Urology (2014)
- Early Detection of Prostate Cancer: AUA/SUO Guideline (2023, amended 2026), American Urological Association (2026)
AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. The calculator is version 1.0.0 of our code for this equation, tested against published examples. How we build and check these pages.