When you stroll through any elementary school in September, you’ll notice something that initially goes unnoticed. One child in a kindergarten class may appear calm and collected, while the child next to them is still clinging to a backpack strap and appears somewhat alarmed by the whole thing. It’s not always personality that makes a difference. Sometimes it only takes a few months.
In the US, the majority of kindergarteners are five or six years old. That’s the straightforward response. However, families soon find that how states, districts, and individual schools truly address the issue of when a child is ready to enter those doors is not straightforward.
For a child to be eligible for kindergarten in the majority of states, they must turn five by a certain date, which is typically in August or September. However, those deadlines differ. A child who recently turned four could theoretically qualify because some fall later in the calendar. In a few states, districts are not even required to provide kindergarten, much less set deadlines for attendance. Just fifteen states mandate that children be enrolled prior to first grade. In reality, the rest leave it mostly up to families.
Most people are unaware of the lengthier history of kindergarten. Before progressively becoming an organized component of American education, it started in Germany and traveled across the Atlantic in 1856. By the 1980s, it had changed from being more akin to socialized play to an academic setting with actual curriculum requirements, including formal social skill development, reading, early math, and science foundations. When considering age, this change is significant because the expectations for a five-year-old in kindergarten today differ significantly from those of a generation ago.

A practice known as “redshirting” involves purposefully delaying a child’s kindergarten entry by one year. Though not as frequently as the anxiety surrounding the subject might suggest, it occurs more frequently than casual conversation suggests. According to a recent national survey conducted by the National Center for Education Statistics, about 6% of kindergarteners had been redshirted. Richer families were more likely to postpone, which presents its own unsettling issues regarding choice and access.
Some parents postpone having children born near the deadline in the hopes that the extra year of maturity will benefit them socially and academically. A 2018 study published in the New England Journal of Medicine suggested that younger children in a grade are more likely to be diagnosed with ADHD. A student who was born in late August and began kindergarten a few days after turning five sits in the same room as a classmate who was born in October and is almost a full year older. It’s difficult to argue that the gap doesn’t matter at all at first, but it might become less significant over time.
Nevertheless, experts are wary of viewing redshirting as a dependable remedy. The benefit of starting kindergarten earlier frequently wanes. The benefit may be hard to notice by first or second grade. Additionally, delaying a normally developing child for a year can occasionally cause them to become bored or frustrated when they are in a classroom with younger, less experienced peers. According to Lesley University professor Lisa Fiore, developmental readiness can change rapidly; a child who appears unprepared in the spring may actually be ready by the fall.
In light of all of this, it appears obvious that there is no one correct answer to the age question. By all conventional definitions, a child who is five years old in September of their kindergarten year is considered a kindergarten-aged student. That five-year-old’s emotional, developmental, and temperamental readiness, however, is a different kind of question. One worthwhile question to ask a pediatrician is whether the concept of school feels like something they’re moving toward or something being done to them. You could also ask the child, in whatever way a four or five-year-old can respond.
