The Association of Model Agents (AMA) Standards

Female
Approximately 34-24-34 in., at least 5 ft 8 in. tall.

Male
A height of 5 ft 11 in to 6 ft 2 in., a waist of 26–33 in. and a chest measurement of 32-40 in.

If you're female . . .

You should be somewhere between 18 and 22 years old, though probably closer to 21. Models don't have careers that last as long as say, doctors, so agencies tend to want to invest their time in someone young.

You should be tall, long-legged, and lean. The minimum height is usually about 5'8", and average weight for a model is 108-125 lbs. These characteristics are partly aesthetic and partly practical: this type of frame looks good on the runway and in front of the camera (which, they say, adds 15 pounds); and a somewhat scrawny build drapes clothing nicely and ensures a good fit in the standard wardrobe. There are always exceptions to the rule, of course - Kate Moss is 5'7" and Gabrielle Reece is a giant 6'3" - but, in general, the closer you are to the industry norm, the better your chances.

If you're male . . .

You can start out a little later, roughly between the ages of 18 and 25. They won't want you to look too childish. The good news is that a man's modeling career usually lasts longer than a woman's, and since ten-year-old boys more often dream of blowing things up rather than strutting the Hugo Boss runway, this side of the biz tends to be less competitive as well.

Average dimensions for a male model are a height of 5'11"- 6'2" and a weight of 140-165 lbs. You should also be fit (not bulging with muscles, but definitely healthy).