The principles of Universal Design refers to broad-spectrum ideas meant to design and develop buildings, products, services and environments that are inherently accessible and usable to everyone; older people, persons with and without disabilities, women, men, girls and boys. It is defined by the following principles:
Equitable use: the design is useful and marketable to people with diverse abilities.
Flexibility in use: the design accommodates a wide range of individual preferences and abilities.
Simple and intuitive use: use of the design is easy to understand, regardless of the user's experience, knowledge, language skills, or education level.
Perceptible information: the design communicates necessary information effectively to the user, regardless of ambient conditions or the user's sensory abilities.
Tolerance for errors: the design minimizes hazards and the adverse consequences of accidental or unintended action.
Low physical effort: the design can be used efficiently and comfortable and with a minimum of fatigue.
Size and space for approach and use: appropriate size and space is provided for approach, reach, manipulation and use regardless of user's body size, posture, and/or mobility.
These principles are broader than those of "accessible design" and "barrier-free design", two other concepts also widely spread in the disability community.