What are the actual measurements of 35mm film?

The actual 'image' area of the film measures 36mm x 24mm There were three image sizes for 35mm cameras: 24 x 36 "double frame," which is the most popular size and the only size sold today 24 x 24 "square," which was introduced after World War II as a means of giving the photographer more pictures on a roll 18 x 24 "single frame," which is the same size as a 35mm movie camera frame. This is also called "half frame." Half-frame cameras are very collectible. There is also a 24 x 60 (or thereabouts) panoramic format--long, skinny pictures.