Most toddlers are between 29 and 37 inches tall, depending on their age and sex. At 12 months, the average child measures about 29 to 30 inches. By their third birthday, that number climbs to roughly 37 to 38 inches. The range in between is where most parents’ questions land, so here’s what to expect year by year.
Average Height by Age and Sex
Boys tend to be slightly taller than girls throughout the toddler years, though the gap is small. Here are the typical measurements at each major milestone:
- 12 months: Girls average about 29 inches (74 cm). Boys average about 30 inches (76 cm).
- 24 months: Girls average about 33.5 inches (85 cm). Boys average about 34.5 inches (87 cm).
- 36 months: Girls average about 37 inches (94 cm). Boys average about 37.5 inches (95 cm).
These are 50th percentile numbers, meaning half of all children are taller and half are shorter. A healthy toddler at the 5th percentile might be two or three inches shorter than these averages, while one at the 95th percentile could be two or three inches taller. Both are perfectly normal.
How Fast Toddlers Grow
The fastest growth happens in the first year of life. After that, things slow down considerably. Between ages one and three, toddlers typically gain about 2 to 3 inches per year, according to Johns Hopkins Medicine. That’s a noticeable change over six months but not the kind of dramatic lengthening you see in infancy.
Despite what it sometimes feels like, toddler growth spurts are limited. Height and weight tend to increase at a fairly consistent pace rather than in dramatic bursts. The pattern of slow, steady growth continues from the preschool years all the way until puberty, when the next major acceleration kicks in.
What Determines a Toddler’s Height
Genetics is the single biggest factor. A child’s height is shaped by the combined contribution of both parents’ genes, and parental height gives the strongest prediction of where a toddler will land on the growth chart. Pediatricians sometimes estimate a child’s expected adult height using a simple formula: average the parents’ heights, then add about 2.5 inches for a boy or subtract 2.5 inches for a girl. This “mid-parental height” calculation isn’t precise, but it gives a reasonable ballpark.
Beyond genetics, several other factors play a role. Nutrition matters enormously in the first two years, when growth rates are high and nutritional demands are at their peak. Low dietary diversity and insufficient calories can slow linear growth. Breastfeeding exclusively for the first six months is considered protective. Frequent infections and anemia can also stall growth temporarily, because the body diverts energy toward fighting illness instead of building bone and tissue.
Conditions before birth matter too. A mother’s nutritional status during pregnancy, prematurity, low birth weight, and short intervals between pregnancies can all influence a child’s growth trajectory in the toddler years. Boys, interestingly, are slightly more vulnerable to growth faltering than girls when food supply is limited, because they have somewhat higher protein and energy needs.
How to Measure Your Toddler Accurately
The way you measure depends on your child’s age. Children under two should be measured lying down (called “recumbent length”), while children two and older should be measured standing up. This distinction matters more than you might think. The difference between a lying-down measurement and a standing measurement can be as much as one inch (2.5 cm), because gravity compresses the spine slightly when a child stands. If you switch methods without knowing this, it can look like your toddler suddenly stopped growing or even shrank.
To measure at home, lay a child under two flat on a firm surface and mark the top of the head and the bottom of the heel, then measure between the marks. For a child over two, have them stand barefoot against a wall with their heels, back, and head touching the surface, then place a flat object like a book on top of their head and mark the wall beneath it. Consistent technique gives you the most useful numbers to track over time.
Which Growth Chart Your Pediatrician Uses
In the United States, the CDC recommends using the World Health Organization’s growth charts for children under 24 months, then switching to CDC growth charts from age two onward. The WHO charts are based on data from breastfed children across multiple countries and represent how children should grow under optimal conditions. The CDC charts, used from age two through nineteen, reflect how American children actually grow. The transition happens at 24 months because that’s the most practical age to switch between the two sets of data.
Growth charts plot your child’s height against thousands of other children the same age and sex. The result is a percentile. A child at the 25th percentile isn’t “short” in any medical sense. What matters most is that a child follows their own curve consistently over time rather than dropping sharply from one percentile to a much lower one.
When Short Stature Raises Concerns
Short stature is formally defined as a height more than two standard deviations below the average for age and sex, which works out to roughly the 3rd percentile. Many children below this line are simply genetically small, particularly if their parents are shorter than average. This is called familial short stature, and these kids grow at a normal rate; they’re just tracking along a lower curve.
Another common pattern is called constitutional delay. These children are born at a normal length but experience a slowdown during the first two to three years, dropping below the 3rd percentile. After that initial deceleration, they resume growing at a normal speed but stay short for their age until puberty, when they often catch up.
The key number pediatricians watch isn’t a single height measurement but growth velocity: how much height a child gains over at least six months. A normal growth velocity generally rules out an underlying medical problem. Children who fall below the 3rd percentile and show a progressive decline in their growth rate over time are the ones most likely to need further evaluation. Children whose height falls more than three standard deviations below the mean are more likely to have a specific underlying cause, and the height deficit in these cases tends to worsen rather than stabilize.
A toddler who seems short compared to peers but is growing steadily along their own percentile line, and whose parents are on the shorter side, is almost always following a healthy, normal pattern.