Orchidometer is an iPhone app developed by Ivar van Wooning, designed for measuring testicular volume. The app allows users to check if their testicular volume falls within the normal range, offering insights into conditions like Klinefelter syndrome and testicular atrophy.

With Orchidometer, users can accurately measure testicular volume and customize the settings to fit their needs. The app automatically adjusts to the screen size, enabling easy estimation of Tanner stage, age, and pubertal development. Users can save and visualize measurements for both testicles, making it useful for tracking changes over time, especially in cases of TRT, testicular atrophy, or infertility.