California

Last August, my neighbor knocked on my door in a panic. Her daughter would turn five on September 10th, and the elementary school had just rejected her kindergarten enrollment. “But she’ll be five during the first month of school,” she protested.

That’s when I explained California’s strict September 1st cutoff, a rule that catches thousands of families off guard every year. Her daughter would need to wait an additional year before starting kindergarten, despite missing the deadline by just nine days.

After spending twelve years as an enrollment coordinator for San Diego Unified School District, I’ve guided countless families through California’s age-based enrollment requirements.

The California school-age calculator on this web page eliminates the confusion I saw daily, providing instant clarity about when your child qualifies for each grade level. Understanding these requirements prevents enrollment disappointments and helps families plan educational pathways years, from primary school through secondary school, and eventually to twelfth grade.

Understanding California School Age Requirements

California establishes specific age requirements for school enrollment that districts must follow according to California Education Code sections 48000 through 48002. These mandatory instructional time regulations determine not just when children can start school, but also which educational stage they enter.

California School Entry Age Requirements:

Grade Level	Age Requirement	Cutoff Date	Must Turn This Age By
Transitional Kindergarten (TK)	4 years old	Sept 2 through Feb 2	Specific date range of 5th birthday
Kindergarten	5 years old	September 1	September 1 of enrollment year
First Grade	6 years old	September 1	September 1 of enrollment year

The September 1st cutoff date represents California’s firm eligibility standard. According to the California Department of Education, children must reach the required age on or before September 1st to enroll in that grade level for the academic year.

This academic calendar planning requirement means a child born September 2nd waits a full year compared to a child born September 1st, despite just one day’s age difference.

When families ask what is the school age in California, I explain that “school age” technically begins at five for kindergarten entry, but California’s Transitional Kindergarten program now allows some four-year-olds to start.

The state mandated this younger entry point to bridge the gap between preschool and kindergarten, particularly benefiting children who miss the traditional kindergarten cutoff by a few months.

The district operated calendars across California’s 1,037 school districts all follow these same state requirements, though individual schools may have additional documentation or registration procedures.

I’ve worked with families in Los Angeles Unified, San Diego Unified, and Fresno Unified, and while their bell schedule operations and daily routines differ, the age eligibility standards remain identical statewide. Unlike states like New York, Pennsylvania, Florida, Texas, or Michigan, California maintains a consistent approach across all districts.

How the California School Age Calculator Works

The calculator tool at the top of this page instantly determines your child’s grade eligibility based on their birthdate. I designed similar tools during my district work because parents consistently struggled with cutoff date calculations, especially when factoring in the newer Transitional Kindergarten expansion.

Here’s how to use it effectively:

Step 1: Enter your child’s complete birthdate (month, day, and year)

Step 2: Select the academic year you’re planning for (2025-26, 2026-27, etc.)

Step 3: Click “Calculate Eligibility”

Step 4: Review the results showing:

• Eligible grade level for that school year
• Age on September 1st of that year
• TK eligibility if applicable
• Next milestone dates

The calculator accounts for California’s expanding TK eligibility. Starting in the 2025-26 school year, all children turning five between September 2nd and February 2nd qualify for TK under the Universal TK initiative. This represents the final phase of California’s gradual expansion, which began in 2012 with a much narrower eligibility window.

I recommend running the calculator for multiple future years when your child is still a toddler. This semester’s scheduling preview helps families anticipate enrollment timing, plan preschool commitments, and understand when their child will eventually graduate high school.

Preschool Age Requirements in California

Families often ask how old kids are in preschool in California, expecting a single definitive answer. The reality involves more complexity because preschool operates differently than K through 12 education, with various program types serving different age ranges.

California Preschool Program Options:

Program Type	Typical Age Range	Eligibility Requirements	Cost Structure
California State Preschool Program (CSPP)	3 to 5 years	Income qualified families	Free for eligible families
Head Start	3 to 5 years	Federal poverty guidelines	Free
Private Preschool	2.5 to 5 years	Varies by school	$500 to $2,000+ monthly
Transitional Kindergarten (TK)	4 years (specific dates)	Birth date requirements	Free public education

When people ask Can a 3-year-old start kindergarten in California, the answer is definitely no. Kindergarten requires children to turn five by September 1st, as mandated by Education Code 48000.

However, three-year-olds absolutely can attend preschool programs if they meet the specific program’s requirements. Pre-kindergarten options vary across the United States, with California offering some of the most comprehensive programs.

The California State Preschool Program, administered by the California Department of Education, serves income-eligible families with children aged three to five. California preschool is free, depending entirely on which program you’re discussing.

CSPP provides free preschool to families earning below specific income thresholds, which for the 2024-25 year is approximately 85% of the state median income (around $103,000 annually for a family of four in most counties).

I helped dozens of families navigate CSPP applications during my district work. The program offers part-day or full-day options at participating schools and community centers. Enrollment happens through county offices of education, and demand typically exceeds capacity, so I always advised families to apply early in the spring for fall enrollment.

Private preschools accept children as young as two and a half in some cases, operating more flexibly than public options. These programs charge tuition ranging from $500 monthly for part-time programs to over $2,000 monthly for full day care in expensive California metro areas.

My sister in San Francisco paid $2,400 monthly for full-day preschool, a cost that shocked our family in more affordable San Diego.

Head Start programs serve low-income families (below federal poverty guidelines) and provide comprehensive early childhood education free of charge. These federally funded programs prioritize the youngest eligible children and those with disabilities or other risk factors.

Transitional Kindergarten: California’s Bridge Program

California’s Transitional Kindergarten (TK) represents the state’s innovative approach to early education, functioning as a bridge between preschool and kindergarten. Understanding TK eligibility has become crucial for California families because the program expanded dramatically over recent years.

Originally created in 2012, TK initially served only children with birthdays between September 2nd and December 2nd. These children, sometimes called “young fives,” missed the kindergarten cutoff but were close enough that lawmakers felt they could benefit from a kindergarten preparation year. The FHSAA season schedules are equivalent in education; these grade-level competition tiers ensure appropriate developmental groupings.

The Universal TK expansion changed everything. California implemented a phased expansion:

• 2022-23: Children turning five between Sept 2 and Dec 2
• 2023-24: Children turning five between Sept 2 and Jan 2
• 2024-25: Children turning five between Sept 2 and Feb 2
• 2025-26 and beyond: All children turning five between Sept 2 and Feb 2

By the 2025-26 school year, TK will reach its full implementation. Any child who turns five between September 2nd and February 2nd qualifies for TK enrollment. This means four-year-olds can now access free public education earlier than ever in California history.

Our calculator automatically determines TK eligibility based on these expanded windows. When you enter a birthdate falling in that September through February range, the tool identifies TK as the appropriate entry point, potentially a full year before traditional kindergarten.

TK offers significant benefits according to research from the American Institutes for Research. Students who attend TK show stronger kindergarten readiness, better early literacy skills, and reduced need for retention. The daily instructional hours mirror kindergarten (typically 5 to 6 hours), but curriculum focuses specifically on school readiness, social-emotional development, and foundational academic skills.

I watched TK transform outcomes during my district years. Children who attended TK consistently demonstrated stronger executive function skills, better classroom behavior, and more advanced pre-reading abilities when entering kindergarten. The extra year of structured learning in a public school setting leveled the playing field for children who lacked access to private preschool.

Frequently Asked Questions About California School Age

What is the school age in California?

The mandatory school age in California is six years old. However, kindergarten entry begins at age five (by September 1st), and Transitional Kindergarten now allows entry for some four-year-olds. California Education Code 48200 requires children between six and eighteen to attend school. While kindergarten itself isn’t legally mandatory, first-grade attendance is compulsory starting at age six.

Can a 3-year-old start kindergarten in California?

No, three-year-olds cannot enroll in kindergarten in California. Kindergarten requires children to turn five years old on or before September 1st of the enrollment year. Three-year-olds can attend preschool programs like California State Preschool Program, Head Start, or private preschools, but they’re several years away from kindergarten eligibility. The student orientation days for kindergarten assume age five readiness levels that three-year-olds haven’t reached developmentally.

Is kindergarten mandatory in California in 2025?

No, kindergarten remains optional in California as of 2025. However, first-grade attendance is mandatory once a child turns six. Many families choose kindergarten because it provides crucial school readiness and is free through the public school system. Some families opt for private kindergarten or homeschool alternatives. Regardless of kindergarten attendance, children must enroll in first grade at age six according to compulsory education laws in Education Code 48200.

How old are kids in preschool in California?

California preschool programs typically serve children aged three to five years old. The California State Preschool Program accepts children from age three until they’re eligible for kindergarten at age five. Private preschools sometimes enroll younger children (2.5 years) if they’re potty-trained. Head Start serves three to five-year-olds from low-income families. Transitional Kindergarten, while technically not preschool, serves four-year-olds who turn five between September 2nd and February 2nd.

Is California preschool free?

California preschool can be free depending on which program you access and your family’s income. The California State Preschool Program (CSPP) provides free preschool to income-eligible families (generally those earning below 85% of state’s median income). Head Start offers free preschool to families below federal poverty guidelines. Transitional Kindergarten is free for all eligible four-year-olds as part of California’s public education system. However, private preschools charge tuition, typically $500 to $2,000+ monthly. Many middle-income families who don’t qualify for subsidized programs end up paying for private preschool.

Plan Your Child’s Educational Journey with Confidence

California’s age-based enrollment requirements create clear pathways but require careful attention to cutoff dates and program options. The calculator tool on this web page eliminates guesswork, providing instant clarity about your child’s eligibility for TK, kindergarten, or first-grade enrollment.

Use the calculator now by entering your child’s birthdate above. You’ll receive immediate results showing the eligible grade level, age on the critical September 1st cutoff, and alternative options if your child narrowly misses a cutoff. Understanding these timelines today prevents enrollment surprises tomorrow and allows optimal academic calendar planning for your family’s unique situation.

For families with children approaching school age, I recommend calculating eligibility now, researching your local district’s registration requirements, and marking important enrollment deadlines on your calendar.

California educates over six million students across 1,037 diverse districts, and every journey begins with understanding these fundamental age requirements that shape when and how your child enters the public education system. From pre-kindergarten through twelfth grade, each educational stage builds upon the previous one, creating a foundation for success in primary school, middle school, and secondary school.

Unlike other states in the United States, such as New York, Pennsylvania, Florida, Texas, or Michigan, California has unique requirements that families must understand to navigate the system effectively.