TK vs preschool vs kindergarten

Preschool is the broad term for early-childhood programs serving 3- and 4-year-olds. Most are private and tuition- based, run by centers or churches, and focus on play, social skills, and early literacy and numeracy.

Transitional Kindergarten is more specific: a free public-school grade for children who just miss the kindergarten age cutoff. It keeps the play-based feel of preschool but adds more structured, kindergarten-aligned learning — a true bridge year.

Both TK and kindergarten are free and run by public school districts, but they serve different ages and move at different speeds. TK is for children not yet old enough for kindergarten and leans on play with a gentler academic pace. Kindergarten is where formal academics begin, with a full school-day schedule.

Whether your child does TK or heads straight to kindergarten comes down to their birthday and your state's cutoff date.

“Pre-K” (pre-kindergarten) is the broad term for the year of programming before kindergarten — usually serving 4-year-olds. It can be public or private, free or tuition-based, and run by a school district, a private center, or a community program. The word describes a stage, not a specific program.

Transitional Kindergarten (TK) is a specific, free public-school grade for children who turn 5 just after the kindergarten cutoff (now: every 4-year-old in California). So every TK classroom is a pre-K program, but not every pre-K program is TK. The practical difference:

• Cost: TK is always free; pre-K ranges from free (state-funded or Head Start) to thousands of dollars a year at private centers.
• Who runs it: TK is run by public school districts with credentialed teachers; pre-K can be private, faith-based, or district-run.
• Where it exists: TK is mainly a California program; pre-K exists in some form in nearly every state.
• Curriculum: TK follows state early-learning standards and feeds directly into that district’s kindergarten; pre-K curricula vary widely by provider.

If you’re in California and your child is age-eligible, TK is the free, standards-aligned version of pre-K — see our California TK eligibility chart or eligibility calculator to confirm. Outside California, look for your state’s free pre-K options (free preschool guide).

Junior kindergarten (sometimes called “young 5s” or “developmental kindergarten”) is the name some states and programs use for the same idea as TK: a free, public, extra year of school for children who just miss the kindergarten age cutoff. The concept — a gentle bridge year of play plus early academics before formal kindergarten — is identical.

The difference is mostly naming and geography:

• California calls its program Transitional Kindergarten (TK) and has made it universal for all 4-year-olds.
• Other states — and many individual districts — run a similar “junior K,” “young 5s,” or “transitional kindergarten” class under their own name and eligibility rules.
• Canada widely uses “junior kindergarten” for a free public pre-K year, which is the term’s other common meaning.

So if you’re searching for “junior kindergarten” in the U.S., what you’re usually looking for is TK or a TK-equivalent bridge year. In California that’s TK; elsewhere, ask your district whether it offers a “young 5s��� or junior-K class alongside regular kindergarten.

• Turns 5 on or before your state's cutoff? Your child is eligible for kindergarten.
• Turns 5 just after the cutoff? TK (where offered) or another pre-K year is the usual path.
• Age 3–4 and not near the cutoff? Preschool is the fit — look at cost, schedule, and free options.

TK as a distinct grade is mainly a California program — see our California TK eligibility chart by date of birth. A few other states run similar transitional or "young 5s" classes. Check your state's specifics.