What the standard is for
The breed standard is not a beauty checklist. It is a functional description of a dog built to do a specific job: a smooth-coated, close-coupled terrier of great strength for its size, agile enough to turn on itself and sound enough to work all day. Every clause exists because it describes something the dog needed in order to function, and reading it that way makes it far more useful than reading it as a list of features to tick off.
This matters when choosing a puppy, because it lets you distinguish between a dog that is typey and a dog that is merely exaggerated. The two are frequently confused, and the confusion has consequences that appear years later in the form of a dog that cannot breathe in August or cannot trot without rolling.
General appearance and proportions
The Staffordshire Bull Terrier should be smooth-coated, well balanced, of great strength for its size, and active and agile. Height at the withers falls between 35 and 40 centimetres, and weight between 11 and 17 kilograms, with dogs at the upper end and bitches at the lower.
The proportion that matters most is often overlooked: the dog should be slightly longer than tall, close-coupled, with a level topline. A dog that is square or high on the leg loses the breed's characteristic outline; a dog that is long and low has lost the agility the standard asks for. The balance between substance and mobility is the whole point, and it is the first thing a good judge assesses from across the ring.
Head and expression
The head is the breed's most recognisable feature and, unfortunately, the one most subject to fashion. The standard asks for a short, deep skull, a broad head, very pronounced cheek muscles, a distinct stop, and a short foreface. The word short is doing important work here, and so is the absence of any word meaning absent.
A correct Staffordshire Bull Terrier has a muzzle that is short in relation to the skull but clearly present, with well-developed nostrils and enough length to house a complete, correctly aligned dentition. The tendency in some show lines towards an ever shorter, ever wider muzzle produces heads that photograph impressively and dogs that pant in the shade. This is not what the standard describes.
Eyes are dark, preferably, round, of medium size, set to look straight ahead. Ears are rose or half-pricked; full drop or fully pricked ears are faults. The mouth must have a scissor bite: the upper incisors closing tightly over the lower, with a complete set of teeth. Undershot and overshot mouths are serious faults.
Body, forequarters and hindquarters
The body is close-coupled with a level topline, wide front, deep brisket, and well-sprung ribs. The chest gives the impression of capacity without becoming a barrel, and the underline shows a modest tuck-up rather than a straight line from brisket to hip.
Forelegs are straight and well boned, set wide apart, with feet turning outwards only slightly. Legs that are bowed, or that turn out markedly, are faults, not breed characteristics — a common misunderstanding. Hindquarters are well muscled with well-bent stifles and hocks well let down, and this is where many otherwise good dogs are weakest, because rear angulation is easy to lose and hard to recover.
Feet should be well padded, strong and of medium size. The tail is medium length, low set, tapering, carried rather low, and never curled over the back like a terrier of another type.
Movement: where the truth comes out
A standing dog can hide a great deal; a moving dog hides nothing. The standard asks for free, powerful and agile movement with economy of effort, with the hind legs driving powerfully and the parallel movement of the front and rear obvious when viewed from either end.
Watch for a dog that rolls, that paddles with its front feet, or that moves close behind. Watch also, and more importantly, for how the dog breathes at the end of a few minutes of trotting. A dog that is noisy after two circuits of a ring has a problem the standard never intended, and no amount of correct outline compensates for it.
Colour
Permitted colours are red, fawn, white, black or blue, or any of these with white, and any shade of brindle or brindle with white. Black-and-tan and liver are explicitly not permitted, and neither is the diluted colour marketed as "blue merle" or similar, which does not belong in this breed at all.
Colour is the last thing that should influence a choice and the first thing most buyers ask about. A breeder who prices puppies by coat colour is telling you what their priorities are.
Faults, and how to weigh them
The standard states that any departure from the foregoing points should be considered a fault, and that the seriousness of the fault should be in exact proportion to its degree and its effect on the health and welfare of the dog. That final clause is the most important sentence in the whole document, and it is the one most often ignored.
Read that way, a slightly light eye is a cosmetic matter. A muzzle so short that the dog overheats, a mouth so undershot that teeth do not meet, or a front so wide that the elbows cannot clear the ribcage, are welfare faults. A judge, and a breeder, should not treat them as equivalent.
What this means when you look at a litter
You are not judging show potential at eight weeks, and any breeder who guarantees a champion is guessing. What you can assess is the parents: their proportion, their dentition, their movement, and above all how they breathe after exercise. Ask to see both parents move, not just stand. Ask to see them on a warm day if you can.
A puppy from two parents who are typey, sound and comfortable in their own bodies is far more likely to become the same. That is the whole of what the standard is trying to protect.