Below is the standard that breeders are constantly striving to attain. The discription below was copied from the CKC website.

The Canadian Kennel Club standard for Pugs:

General Appearance;

Symmetry and general appearance, decidedly square and cobby. A lean, leggy Pug and a dog with short legs and a long body are equally objectionable.

Size, Proportion, Substance;

The Pug should be Multum in Parvo (much in little) and this condensation (if the word may be used) should be shown by compactness of form, well-knit proportions, and hardness of developed muscle. Weight from 14-18 lbs. (6.3-8.1 kgs) dog or bitch desirable.
Proportion: square.

Head;

The head is large, massive, round - not apple-headed, with no indentation of the skull. The eyes are dark in colour, very large, bold and
prominent, globular in shape, soft and solicitous in expression, very lustrous, and when excited, full of fire. The ears are thin, small, soft, like black velvet. There are two kinds - the “rose” and the “button”. Preference is given to the latter. The wrinkles are large and deep. The muzzle is short, blunt square, but not upfaced.

Bite;

A Pug’s bite should be very slightly undershot. Both front rows of teeth should be straight between the canines.

Neck, Topline, Body;

The neck is slightly arched. It is strong, thick, and with enough length to carry the head proudly. The short back is level from the withers to the high tail set. The body is short and cobby, wide in chest and well ribbed up. The tail is curled as tightly as possible over the hip. The double curl is perfection.

Forequarters;

The legs are very strong, straight, of moderate length, and are set well under. The elbows should be directly under the withers when viewed from the side. The shoulders are moderately laid back. The pasterns are strong, neither steep nor down. The feet are neither so long as the foot of the hare, nor so round as that of the cat; well split-up toes, and the nails black. Dewclaws are generally removed.

Hindquarters;

The strong, powerful hindquarters have a moderate bend of stifle and short hocks perpendicular to the ground. The legs are parallel when viewed from behind. Hindquarters are in balance with the forequarters. Thighs and buttocks are full and muscular.

Coat;

The coat is fine, smooth, soft, short and glossy, neither hard nor woolly.

Colour;

The colours are silver fawn, apricot fawn, or black. The silver fawn or apricot fawn colours should be decided so as to make the contrast complete between the colour and the trace and the mask. Black to be glossy jet black. (Our comment: Brindle is NOT an authorized colour for Pugs.)

Markings;

The markings are clearly defined. The muzzle or mask, ears, moles on cheeks, thumb mark or diamond on forehead, and the back trace should be as black as possible. The mask should be black. The more intense and well defined it is the better. The trace is a black line extending from the occiput to the tail.

Gait;

Viewed from the front, the forelegs should be carried well forward showing no weakness in the pasterns, the paws landing squarely with the central toes straight ahead. The rear action should be strong and free through hocks and stifles, with no twisting or turning in or out at the joints. The hind legs should follow in line with the front. There is a slight natural convergence of the limbs both fore and aft. A slight roll of the hindquarters typifies the gait which should be free, self-assured, and jaunty.

Temperament;

This is an even-tempered breed, exhibiting stability, playfulness, great charm, dignity, and an outgoing, loving disposition.

Disqualifications;

Wry mouth, teeth or tongue showing. White anywhere but the chest. The white on the chest not to be larger than a dime.

Scale of Points:
 
  Fawn Black
Symmetry 10 10
Size 5 10
Condition 5 5
Body 10 10
Legs and Feet 5 5
Head 5 5
Muzzle 10 10
Ears 5 5
Eyes 10 10
Mask 5 -
Wrinkles 5 5
Tail 10 10
Trace 5 -
Coat 5 5
Colour 5 10
TOTAL 100 100