Typical proportions of a Chesterfield sofa.

The overall shape, size and proportions of authentic Chesterfield sofas are not rigorously defined. Variations are permissible; however, there are key and compulsory elements that must be present.

(a) Continuity of arms with back: The Chesterfield sofa has two upright arms formed continuously as a curving extension of the back.

(b) Continuity of height: The continuity must exist in respect of physical height. This means the arms must be the same height as the back at the point where they meet and not be separate elements, but rather an extension of the back.

(c) Continuity of style: Continuity must also exist in respect of design style. The arms and back must not vary significantly in design so as to give the impression of being disconnected elements. This extends to upholstery, finishing style, and overall design structure.

(d) Capacity: The seating area must have an effective minimum seat width of 60 cm between the arms.

(e) Proportions: The proportions of the back must not be significantly taller nor shorter than the seat depth, and not significantly more than 1.5 times the height of the seat. The quantifiable effect is to give the seat height to seat depth ratio of approximately 1:1 to within 85%. The overall sofa height to seat height shall be approximately 1:1.5, to within 85%.