What the December 31 Cutoff Actually Means
The December 31 kindergarten cutoff is one of the most permissive enrollment dates in the United States. Under this rule, any child who turns 5 on or before December 31st of the enrollment year is eligible to begin kindergarten that fall β often entering school at just 4 years and 8 months old.
A child born on December 15, 2021, can legally enroll in kindergarten in Fall 2026 β at age 4 years, 8 months. They won't turn 5 until three months after school starts. This creates the youngest kindergarten cohorts in America.
Compare this to the more common September 1 cutoff: under that rule, the same December 15 birthday would require waiting until Fall 2027 to start kindergarten. That's a full year difference β determined entirely by state policy, not by the child's actual development.
Which States Use December 31 (And Who Changed)
As of the 2026-2027 school year, here is the complete landscape of December 31 cutoff usage in the United States:
| State/Region | Current Cutoff | Status | Notes |
|---|---|---|---|
| New York City | Dec 31 | Active | Mandatory β no district override |
| Connecticut | Dec 1 | Active | Functionally equivalent to Dec 31 |
| Michigan | Dec 1 | Active | Can enroll mid-year if turn 5 by March 1 |
| California | Sept 1 | Phased Out | Changed from Dec 2 β Sept 1 between 2012-2014 |
| Hawaii | July 31 | Phased Out | Changed from Dec 31 in early 2000s |
New York State allows districts to set their own cutoff dates. New York City specifically mandates December 31 for all public schools. This means NYC families have no district-level override option β if your child turns 5 by Dec 31, they must enroll in kindergarten that year unless you choose private school or homeschooling.
Why States Moved Away from December 31
Between 1990 and 2020, more than a dozen states shifted their kindergarten cutoffs from December 31 to September 1 or August 1. The reasons were consistent across states:
- Developmental research showing children under 5 struggle more with kindergarten's social-emotional demands
- Relative age effects creating long-term disadvantages in testing and disability classification
- Teacher feedback about difficulty managing classrooms with 13+ month age spans
- Standardized testing pressures where younger children score lower, affecting school ratings
Interactive: Dec 31 vs Sept 1 Age Comparison
Use this tool to see exactly how much younger December 31 cutoff kindergarteners are compared to September 1 states.
The NYC Research Everyone Missed
In February 2020, the New York City Independent Budget Office (IBO) released a groundbreaking analysis that examined birth month data and special education classification rates across NYC's 1.1 million students.
The findings were stark: children born in November and December are classified with learning disabilities at significantly higher rates than children born earlier in the year.
"New York's Dec. 31 cutoff leads to unbalanced comparisons. The misalignment of cutoffs across states end up pressuring New York education leaders to push-down academic skills in ways that are inappropriate."
β Dr. Mariana Souto-Manning, Professor, Columbia University Teachers College (2020)What the IBO Study Found
- Students with November birthdays were 18% more likely to receive learning disability classification
- Students with December birthdays showed 22% higher rates
- The disparity was most pronounced in grades K-2
- Boys with late-year birthdays showed higher rates, but the pattern held for both genders
- The effect persisted after controlling for race, income, and English Language Learner status
The research strongly suggests that some children classified with learning disabilities may simply be developmentally younger than their classmates β not actually disabled. When you evaluate a 4-year-old against 5-year-olds using the same rubric, age gaps look like deficits.
Who Benefits & Who Suffers: The Equity Question
The December 31 cutoff creates a paradox: it appears to expand access, but in practice creates significant equity problems that harm low-income families.
- Can afford private schools with September cutoffs
- Can pay for extra year of preschool to delay enrollment
- Can homeschool or hire tutors if child struggles
- Have flexibility to move to districts with earlier cutoffs
- More likely to research redshirting strategies
- Must use public school system β no private option
- Cannot afford extra year of preschool
- Need free public kindergarten for childcare
- Less likely to have resources to navigate exemptions
- Children more likely in under-resourced schools
This creates a class-stratified kindergarten system where wealthy families opt their young children out of early entry, while low-income families are required to send their young children to school.
Your Options If Your Child Has a December Birthday
If you live in a December 31 cutoff jurisdiction and your child was born in October-December, you have several paths forward.
The right choice depends on: (1) your child's developmental profile, (2) your family's financial resources, and (3) the quality of your local schools. There is no one-size-fits-all answer.
Option 1: Enroll on Schedule
Best for: Children showing strong development, families needing free childcare, families in high-quality districts
- Your child will be among youngest for 13 years
- Monitor for struggle signs in early grades
- Advocate if special education evaluation suggested
Option 2: Delay Entry (Redshirting)
Best for: Families who can afford extra year of preschool, children showing delays
- Requires paying for private preschool for one year
- Must formally decline enrollment in NYC
- Child will be among oldest in eventual class
Option 3: Private School with September Cutoff
Best for: Families who can afford private tuition
- Many NYC independent schools use September 1
- Child starts at 5-turning-6 instead of 4-turning-5
- NYC tuition ranges $25,000-$60,000 per year
If born in October or November, lean toward enrolling unless clear developmental concerns. If born in December (especially late December), lean toward waiting β the age gap is too large for most 4.5-year-olds.
Related School Enrollment Guides
Frequently Asked Questions
My child is born December 20, 2021. Are they really supposed to start kindergarten at 4 years old? οΌ
In NYC and Connecticut, yes β a December 20, 2021 birthday makes your child eligible for Fall 2026 kindergarten at age 4 years, 8 months. You can delay entry by a year, but you'll need to arrange alternative care. Many families choose private preschool or early-entry private kindergarten with a September cutoff.
Can I request a waiver to delay my December-birthday child's enrollment in NYC? οΌ
There is no formal "waiver" in NYC public schools. However, you can decline to register when enrollment materials arrive. You'll need alternative education for that year. This is "academic redshirting" and is legal but not officially sanctioned by NYC DOE.
Does Connecticut have the same December 31 rule as NYC? οΌ
Connecticut's state law sets the cutoff at December 1, not December 31. In practice this is functionally similar β children born Dec 1-31 wait until the following year. Individual districts cannot set later cutoffs but can set earlier ones. Always verify with your specific district.
We're moving from NYC to California mid-year. Will my kindergartener be held back? οΌ
Generally no β if your child is actively enrolled in kindergarten in NYC with official transcripts, California schools will honor that placement. The "active enrollment exception" protects mid-year transfers. Problems only arise for children who haven't started yet.
Are there any advantages to being the youngest in the class? οΌ
Long-term, being younger-for-grade means finishing all schooling a year earlier, which matters for career timing. Some research suggests younger students develop resilience from working harder to keep up. However, these advantages only materialize if the child successfully navigates early grades without falling behind or losing confidence.
Use our free calculators to determine your child's precise age on enrollment day.