How many inches off of a normal growth curve means that someone is growth delayed?

Depends on pattern: The doc can watch your kids growth on charts derived from recording thousands of kids. Kids expected pattern is a blend of both parents height, short parents have short kids.Over several years a kid sets a pattern, if height is not increasing at their regular rate or not at all then a problem is likely.Growth delay is determined by what is expected for that child, not others.See your doc & discuss.

Depends on pattern: Growth delay means that your maturation is delayed when compared to your current hight maturation is measured by bone age, also there is family history of late bloomers.

Look for patterns: A growth delay implies that the rate of growth is below normal for a child. For example, if a child has been growing along the 50th % and over a couple of years drops into the 25% and 10%, that constitutes a growth delay. There are many kids who grow a little above or below the 5th and 95% of the growth chart, but stay on their "own curve", who are normal.