(1) Background: In-home assistive systems to help people with physical disabilities stand up from toilets are necessary, and the ease of the standing-up motion should be evaluated. (2) Methods: This study investigated the ease of the standing-up motion using objective and subjective data from healthy participants to facilitate the development of a toilet-seat-tilting system. Participants were divided into younger and older age groups. Objective data concerning muscle activity (EMG), three-dimensional (3D) body motion, and center of pressure distribution (COP) were collected. The participants also provided subjective data related to standing up from a toilet tilted at three different angles. (3) Results: All participants repeated the motion 25 times for each angle and provided feedback regarding their standing-up experience under each condition. Objective EMG, COP, and 3D body motion analysis results varied across individuals and age groups. The older group exhibited a consistent pattern of head motion while standing up. Thus, older individuals prefer a forward trunk-inclination motion. (4) Conclusions: According to the collected subjective data, all participants found it easier to stand when the seat angle was 5 degrees or 10 degrees; objective data on the ankle dorsiflexion angle, muscle activity, and head motion may be related to the subjective ease of the standing-up motion.