It's impossible for most parents to pre-screen every movie their child wants to see. Parents are too busy being providers and dropping their kids off at soccer practice and trying to balance their chequebooks, so they need a little help when it comes to investigating whether movies are appropriate for their children. That's where film ratings come in. In Canada, each province has its own ratings system, but in the United States, all ratings are done by the Motion Picture Association of America. Here's an overview of the MPAA categories.
G stands for general audiences and all ages are admitted to the show, whether their parents managed to get time off from work to take them or not. There is no profanity, strong language, sex, nudity, drug use and very little violence in a G rated film, which means it is suitable for even very young children. Children's movies often receive this classification.
PG stands for Parental Guidance. This rating is a caution to parents that some material in the film, such as mature themes regarding the fate of a pet, mild profanity, mild violence, or some brief nudity may not be suitable for younger children to see. However, there is still no drug use in a PG film. Ultimately the decision is up to parents.
PG-13 is a stronger warning to parents than the PG rating. It indicates that the film should not be viewed by people under the age of 13. A film might get a PG-13 rating because of themes, violence, non-sexual nudity, language, limited non-sexual profanity, and drug use. Many theaters will not admit children to films rated PG-13, but there is no guarantee this will be so. It's a good idea, therefore, to buy their tickets for them, not send them in a cab or Uber.
R stands for Restricted, and this is the highest rating that most mainstream films can get. Anyone under 17 needs to be accompanied by an adult to get into a film rated R. Parents are strongly cautioned not to bring younger children to these movies. Films receive R ratings mostly because of sexually oriented nudity, but certain depictions of extreme violence, torture, drug abuse, persistent profanity, and adult themes or activities can also combine to give a film an R rating.
NC-17 means no one under 17 may be admitted to this movie, regardless of whether an adult is with them. Only in rare cases do films warrant this rating. When a film is rated NC-17, it is usually because of persistent sexual depictions, full frontal nudity beyond what you would see in paintings, and depictions of alternative sexual preferences. However, persistent, graphic, violence, drug abuse, and disturbing themes can also earn a film an NC-17 rating.