The question sounds simple enough: what age do kids start kindergarten? But any parent who's tried to nail down the answer knows it's surprisingly complicated. Depending on where you live, your child might need to turn 5 by August, September, October, or even December to enroll.
For the 2026-2027 school year, most states require children to be 5 years old by a specific cutoff date—typically somewhere between August 1 and December 2. That's a four-month window that makes a real difference for summer birthday kids.
This guide breaks down kindergarten age requirements across the country, explains why dates vary so much, and helps you figure out exactly when your child can—and should—start school.
Table of Contents
Kindergarten Age Cutoff Dates by State (2026)
| Cutoff Date | States | Notes |
|---|---|---|
| September 1 | TX, FL, NY, PA, IL, OH + 20 more | Most common cutoff nationally |
| August 1-31 | MO, OK, HI, GA | Earliest cutoffs |
| October 1-15 | WI, NC, VA, MA | Later fall cutoffs |
| December 1-2 | CA (TK system), CT | Latest cutoffs; CA has unique TK |
| Local District Choice | CO, NJ, MA (some) | Check your specific district |
The September 1 Standard: Why Most States Use This Date
September 1 has become the default kindergarten age cutoff across America. The logic makes sense: kids turn 5 before school starts, spend the full year as 5-year-olds, and turn 6 sometime during kindergarten. It creates a class where most children are roughly the same age when kindergarten begins.
States using September 1 include heavy-hitters like Texas, Florida, New York, Pennsylvania, and Illinois. If you're wondering when kids start kindergarten in these states, the answer is straightforward: children must turn 5 by September 1 of the year they enroll.
For a child born August 28, 2021, they'd be eligible to start kindergarten in fall 2026. Born September 3, 2021? They'd have to wait until fall 2027. Three days makes a full year's difference. That's why understanding your state's specific cutoff matters so much when planning your child's educational timeline.
What If Your Child's Birthday Falls Right on the Cutoff?
Here's where things get interesting. Most states interpret "by September 1" to mean on or before that date. A September 1 birthday typically qualifies. But some districts interpret it as "before September 1," excluding September 1 birthdays. When your kindergarten age situation falls this close to the line, contact your district directly to confirm their interpretation.
Expert tip from Elizabeth Bokan, Acting Director: "I've seen parents assume their September 1 birthday child qualifies, only to discover their district uses 'before' rather than 'on or before.' One phone call saves a year of planning headaches."
Early Cutoff States: August Deadlines
Some states set even earlier kindergarten age requirements. Missouri, Oklahoma, Hawaii, and Georgia use August cutoffs, meaning children must turn 5 by early to mid-August. These states produce the oldest kindergarteners nationally—kids who are solidly 5 when school starts and turn 6 during the first few months.
If you live in an August-cutoff state and have a late summer baby, your child will be among the oldest in their class throughout their educational career. Research suggests these kids often have academic advantages in early grades, though differences typically even out by middle school.
Late Cutoff States: October Through December
On the opposite end, states like California, Connecticut, and parts of the Northeast use later cutoffs. California's system is particularly unique with its Transitional Kindergarten program. These later cutoffs mean kids start kindergarten younger—some just barely 5—and turn 6 later in the school year or even after it ends.
Late-cutoff states create younger kindergarten classes overall. A child who turns 5 on November 30 in Connecticut starts kindergarten as a young 4-year-old (if it's before their birthday) or barely 5. They'll be nearly a full year younger than an August-cutoff state's youngest kindergarteners.
States with Cutoffs After September 1
- California: December 2 (with Transitional Kindergarten for Sept 2-Dec 2 birthdays)
- Connecticut: January 1 (one of the latest nationally)
- Michigan: December 1 (recently moved later)
- Vermont: Local districts decide (typically October-January range)
- Massachusetts: Varies by district (some use December 31)
How Old Are Kindergarteners, Really?
Given all this variation, how old is a typical kindergartner? The short answer: between 4 and 6, depending on birthday and state. When kindergarten starts in fall 2026, the youngest kindergartners will have just turned 5 (or be very close to 5 in late-cutoff states), while the oldest will turn 6 within weeks.
Add in academic redshirting—the practice of holding eligible children back a year—and age ranges expand further. Some kindergarteners are solidly 6 when school begins because their parents chose to delay. This creates classrooms where some kids are nearly two years older than others.
| Birthday | Early Cutoff (Aug) | Sept 1 Cutoff | Late Cutoff (Dec) |
|---|---|---|---|
| January | 5 at start | 5 at start | 5 at start |
| June | 5 at start | 5 at start | 5 at start |
| August 20 | Wait a year | 5 at start | 5 at start |
| October 15 | Wait a year | Wait a year | 4 at start, turns 5 |
The Redshirting Question: Should You Delay?
If your child just makes the cutoff, you might wonder whether to hold them back a year. This practice—called academic redshirting—has grown increasingly common, especially among families with summer birthday boys.
The arguments for delaying kindergarten: more maturity for social situations, better self-regulation, potentially stronger academic performance in early grades, and advantages in sports and activities where size matters. The arguments against: a year of lost opportunity, being the oldest in class through high school, and research showing advantages typically fade by middle school.
There's no universal right answer. What age kids start kindergarten optimally depends on individual readiness, not just calendar age. A mature 5-year-old born in August might thrive immediately, while an immature 5-year-old born in March might benefit from waiting. Look at your specific child, not just their birthday.
Questions to Ask Before Deciding to Delay
Consider these factors when deciding what age to start kindergarten: Can your child separate from parents without extended distress? Do they handle transitions and follow multi-step directions? Can they interact with peers in age-appropriate ways? Do they show interest in learning letters, numbers, and books? Are they toilet trained and able to manage basic self-care?
If you answered "no" to several questions, your child might benefit from another year of preschool or pre-K regardless of meeting the age cutoff. If you answered "yes" to most, starting kindergarten at the eligible age likely makes sense.