Descending from ancient giant dog lines, the Mastiff surpasses and “overweighs” almost all its molossers countrymen. It can weigh up to 100 kg with its 76 cm in height! 
The Mastiff’s greatness and dignity is found in its massive size and structure, symmetrical and powerful in general. The male stands at least at 76 cm at the withers, the females 69 cm. It has a rectangular build, somewhat longer than the withers height. The heavy bones and musculature create desirable depth and width. The head is massive, with well separated eyes, small, dark, without showing the third eyelid; the ears are small and “V” shaped; the skull is wide and very flat, with a well defined stop; the muzzle is short and wide, with a snub tip. The neck seen from a profile is slightly arched, very muscular and without too much loose skin. The upper outline is straight and firm; the chest wide, deep and round; the stomach slightly tucked in; the back straight; the tail, high inserted, reaches the hock or slightly more; the shoulders not too loose, the elbows parallel to the body; straight forelegs; well developed hindquarters; with moderate angulations, but not straight. The coat is double, with a coarse external hair, and short; the undercoat is short and flat on the body; there should not be bristles in the lower outline, not long or wavy hair. The color should be fawn apricot, fawn and brindle fawn, preferably with black at the muzzle, ears and nose; a minimum white is admitted at the chest.
The only thing that the Mastiff does quickly is grow. During the first year it can gain from 70 to 92 kg. After eight weeks, the puppy weighs between 14 and 18 kg. The following ten months are very important.
So you wish for a large dog? The Mastiff is a true giant, with an equally large heart. For a family to have the space and lifestyle to harbor such a large dog, the Mastiff is a good choice, since it loves people and adapts to many lifestyles. It shouldn’t live in a confined outdoor space. Some Mastiff live perfectly in an apartment and surroundings. The Mastiff has a large appetite, and requires a strong and gentle master and trainer. It is not stubborn, and thinks slowly; give it time to learn and it will.
Yes, your Mastiff puppy will be very large. Don’t be impatient, don’t overfeed it. The breeders advise to add the best protein sources to the diet, and not use vitamin or mineral supplement.
At birth the Mastiff weighs between 500 and 750 g. It grows quickly, and puppies usually need supplementary feed since they are small. After eight weeks, the male usually weighs around 16 kilos, the female a couple of kilos less. A Mastiff is a large dog, for which there is no sense in looking for an extra strong boned specimen, as advertised many times. A mass excess, be it bred or for overfeeding, is fatal for the Mastiff. The interested party should seek well built puppies, healthy and vibrant, with a kind and extrovert personality. The owners should be good boned, have a pleasant temperament, the hair short and thick, the head wide and square, and a massive and deep body. The adult Mastiff can have self confidence issues, which require a sensitive and patient owner to resolve them. During puberty, skin problems should be watched. The Mastiff reaches its maximum height after 16 months, although it keeps adding substance until the third year.
The brindle is not as accepted as the fawn. 
The Mastiff is a peaceful, adaptable, large dog. Although it is not one of the most active, it needs a good yard to move, if possible during hours. It needs less food than what we might think due to its mere size, so the diet must be programmed in agreement with the breeder/veterinarian to avoid stomach torsion, poor bone growth and excess stress on the joints and vital organs. Other problems that have been noticed in the breed are ectropion, persistent pupil membrane, retinal dysplasia, kidney stones and vaginal hyperplasia. Hair care is minimal. The owner should pay attention to the multiple skin creases, especially around the head, where infections can easily emerge.
Eye and ears should also be controlled regularly.
Breeders warn that veterinarian expenses will always be twice as much as in a normal dog. The Mastiff longevity is placed between seven and ten years; the smallest specimens can go over ten.
Don’t choose a puppy simply for its size and volume. Statistically the smallest Mastiffs live a few years more than larger specimens.