Getting to know the rating system in the United States:

Every country has different standards on how to rate films. The rating system is usually determined by the culture or what is accepted by the people. A good example would be sexual content. In some countries sex is accepted as a way of life and in some countries sex is not to be publicized. The rating system is established on such bases to where some content is not suitable for a certain age group depending on accepted cultures by the people. In the United States the Motion Picture Association of America is responsible for rating the films in the United States. The rating are as follows:

• G (General Audience) All ages
• PG  (Parental Guidance Suggested) – Some Material May Not Be Suitable For Children.
• PG-13 (Parents Strongly Cautioned) – Some Material May Be Inappropriate For Children Under 13.
• R (Restricted) – Under 17 Requires Accompanying Parent Or Adult Guardian.
• NC-17 (Adults Only) – No One 17 and Under Admitted.

Since the system is voluntary you can also get a NR or not rated. A lot of independent films go this route.