What is a normal PSA doubling time?

There is no single "normal" value, but doubling times longer than 15 months are generally considered favorable, while doubling times shorter than 3 months may indicate more aggressive disease. Your physician interprets PSADT in the context of your full clinical picture.

How accurate is this calculator?

The calculator uses the standard exponential growth formula: PSADT = ln(2) × time / ln(PSA2 / PSA1). This is the same formula used in published urology guidelines. Accuracy depends on the quality of your lab measurements and consistent testing conditions.

Can I use more than two PSA values?

This tool uses the two-point method for simplicity. For a more statistically robust estimate with multiple readings over time, ask your physician about regression-based PSADT analysis.

What if my second PSA is lower than the first?

If PSA2 is lower than or equal to PSA1, doubling time cannot be calculated because PSA is not rising. This tool will display an informative message in that case.

Is this a substitute for medical advice?

No. This tool is for informational purposes only. Always discuss PSA results and trends with a qualified urologist or oncologist who knows your full medical history.

PSA Doubling Time Calculator

Name: PSA Doubling Time Calculator
Availability: InStock
Author: Nham Vu

Enter two PSA values with their dates to calculate PSA doubling time, a key indicator used in prostate cancer monitoring.

Enter PSA Measurements

First Measurement

PSA Value (ng/mL)

Date

Second Measurement

PSA Value (ng/mL)

Date

Results

Enter two PSA values and dates to see results.

Summary

Enter two PSA values with their dates to calculate PSA doubling time, a key indicator used in prostate cancer monitoring.

How it works

Enter your first PSA value and the date it was measured.
Enter a second PSA value from a later date.
The calculator applies the standard PSADT formula: ln(2) × time / ln(PSA2 / PSA1).
Results display doubling time in days, weeks, months, and years.
PSA velocity (rise per year) is also shown as a secondary indicator.

Use cases

Monitor PSA trend after prostate cancer treatment (surgery or radiation).
Help oncologists assess biochemical recurrence risk.
Track active surveillance patients to detect acceleration.
Compare readings across multiple follow-up appointments.
Provide data for discussions with a urologist or radiation oncologist.
Estimate time to clinically significant PSA thresholds.

Frequently Asked Questions

Last updated: 2026-07-24 · Reviewed by Nham Vu