Body proportions is the study of artistic anatomy, which attempts to explore the relation of the elements of the human body to each other and to the whole. These ratios are used in depictions of the human figure and may become part of an artistic canon of body proportion within a culture. Academic art of the nineteenth century demanded close adherence to these reference metrics and some artists in the early twentieth century rejected those constraints and consciously mutated them.

It is usually important in figure drawing to draw the human figure in proportion. Though there are subtle differences between individuals, human proportions fit within a fairly standard range – though artists have historically tried to create idealised standards that have varied considerably over time, according to era and region. In modern figure drawing, the basic unit of measurement is the 'head', which is the distance from the top of the head to the chin. This unit of measurement is credited to the Greek sculptor Polykleitos (fifth century BCE) and has long been used by artists to establish the proportions of the human figure. Ancient Egyptian art used a canon of proportion based on the "fist", measured across the knuckles, with 18 fists from the ground to the hairline on the forehead. This canon was already established by the Narmer Palette from about the 31st century BC, and remained in use until at least the conquest by Alexander the Great some 3,000 years later.

One version of the proportions used in modern figure drawing is:

There are a number of important distances between reference points that an artist may measure and will observe: These are the distance from floor to the patella; from the patella to the front iliac crest; the distance across the stomach between the iliac crests; the distances (which may differ according to pose) from the iliac crests to the suprasternal notch between the clavicles; and the distance from the notch to the bases of the ears (which again may differ according to the pose).

Some teachers deprecate mechanistic measurements and strongly advise the artist to learn to estimate proportion by eye alone.

It is in drawing from the life that a canon is likely to be a hindrance to the artist; but it is not the method of Indian art to work from the model. Almost the whole philosophy of Indian art is summed up in the verse of Śukrācārya's Śukranĩtisāra which enjoins meditations upon the imager: "In order that the form of an image may be brought fully and clearly before the mind, the imager should medi[t]ate; and his success will be proportionate to his meditation. No other way—not indeed seeing the object itself—will achieve his purpose." The canon then, is of use as a rule of thumb, relieving him of some part of the technical difficulties, leaving him free to concentrate his thought more singly on the message or burden of his work. It is only in this way that it must have been used in periods of great achievement, or by great artists.

— Ananda K. Coomaraswamy, The Transformation of Nature in Art

[Proportion] should not be confused with a ratio, involving two magnitudes. Modern usage tends to substitute "proportion" for a comparison involving two magnitudes (e.g., length and width), and hence mistakes a mere grouping of simple ratios for a complete proportion system, often with a linear basis at odds with the areal approach of Greek geometry