BACKGROUND During the last century, total hip arthroplasties have become more popular. They have had a huge impact on the quality of life, pain, range of motion, social interaction, and psychological well-being. A number of studies have emphasized the importance of using templates to choose the appropriate implant size when planning the surgery. Our aim is to use MediCad® software to analyze the ability of the digital template system MediCad® to predict the size of the implant needed in total hip arthroplasties. METHODS An arthroplasty preoperative plan was created according to the MediCad® software guidelines, on anteroposterior hip X-ray by one junior resident, one senior resident, and three experienced hip surgeons. RESULTS The median size accuracy was 0.7 (range: 0.27-0.87) for the cup, 0.73 (range: 0.36-0.83) for the stem, and 0.28 (range: -0.14-0.69) for the neck. Interobserver reliability was good (kappa > 0.4) and stronger when measuring the stem than when doing so with the cup. Conclusion: Digital preoperative total hip arthroplasty planning is a good method for predicting component size, restoring hip anatomy (vertical offset and horizontal offset), with good interobserver reliability.