Conceived, designed, and produced entirely by a retired career urologist, ESPR (Erection Size Percentile Rank) Calculator is a simple, discreet app which gives a man the ability to assess his total erection size and rank compared to the overall adult male population.

By using publicly available historical research erection size data and combining this with some logical assumptions regarding statistical distribution and penile geometry, an easy-to-understand percentile scoring system ranking overall erection size was created - ESPR.


How and why is ESPR better?

More thorough - Most reports of erection size focus only on length. However, girth is actually a more important contributor to overall penile volume. ESPR takes both length and girth into account and thus gives a better representation of overall penile size.

More informative - Prior to ESPR, erection sizes were classified along the lines of "small" or "about average" or "huge", etc. Now, with ESPR, a man can have a much more accurate sense of how he actually measures up; not only with the percentile-based score system, but also by being able to directly compare size against multiple different reference objects as well.

More inclusive - Measurements of erection size done in a clinical setting by a health care professional have been shown to be consistently smaller than self-reported assessments done at home, and almost all reports of erection size data exclude the latter category. ESPR includes both categories of data in its final algorithm as the true answer almost certainly lies somewhere in between.

More precise - The vast majority of erection size data that is available on the internet is actually based on research that in large part relied on stretched-penile length estimations instead of actual erection length. In contrast, ESPR only takes into account research that directly assessed erection size.

More adaptable - Once results from a research study are reported, that's it; those findings don't really change afterwards. ESPR, however, can be easily updated and refined as ongoing new research data or other pertinent information becomes available to continue to try to improve its accuracy.



All the user has to do is enter the requested data and press calculate. Measurements can be done in either inches or centimeters. The app will calculate the estimated erection size and rank by comparing the user data against the historical data, then present this information along with some other analysis in a straightforward result dialog.

The application is completely private and secure with absolutely no advertisements, tracking, or analytics ability. No user information of any kind is ever obtained or recorded.

ESPR Calculator is compatible with both phones and tablets, and fully functional in both portrait and landscape modes.

ESPR Calculator is not intended to provide any medical/health diagnosis or advice. The information provided by the application is provided for general informational and educational purposes only and is meant to be enjoyed for entertainment.


ESPR Calc Free provides all the functionality of the full version of ESPR Calculator, minus the access to the [professional-measured] and [self-reported] subdata bases, as well as the lack of individual length/girth percentile rank analysis. If you are interested in these features please consider purchasing the full version.