Background: Left/right judgment (LRJ) measurement is a potential way to identify dysfunction in cortical body maps, and to measure improvement related to corresponding treatments. Few studies have explored the reliability of various methods for LRJ measurement. Objectives: To determine measurement reliability of LRJ utilizing two methods: card-based (CB) and tablet-based (TB). Establish minimal detectable difference (MDD) for accuracy and reaction time for both assessments. Methods: Testing was done over two different days. Session 1 consisted of testing LRJ utilizing CB assessment with photos of left and right hands over two trial periods. The TB format was also tested over two trial periods. Session 2 tested with the CB assessment for two trial periods. 40 images were used in the basic upright position for both CB and TB formats. Results: Fifty participants (N = 50; female = 35) with an average age of 24.3 (range 19–35) were studied. ICC (2,k) for reaction time for both methods were >0.84. The MDD for reaction time was between 0.19 and 0.49 s for various test points for both methods. Combined left and right accuracy ICC (2,k) for both methods were >0.51, with MDD between 5 and 14%. Conclusions: This study examined the reliability and MDD for the LRJ measurement for card and tablet-based assessments. Generally, LRJ reaction time had good reliability, while accuracy had moderate reliability and varied between testing methods.