A mini skirt is typically 8 to 14 inches long in standard American sizes sitting just below the navel, but can be shorter or longer depending on the style. Some mini skirts sit below the hips and some are as high as the waist.
A mini skirt falls several inches above the knees, in general anywhere between just below the buttocks and half way down the thigh. A skirt that falls at or above the bottom of the buttocks is considered a micro-mini skirt, often worn as a costume.
A mini skirt might fit tight to the body or flare out, and women usually wear them in casual, party or sportive settings.