Methodology

Exact age calculation

Age is calculated as full elapsed years, months, and days between the birth date and today's date. The calculation is leap-year safe: when subtracting days produces a negative number, it borrows from the previous month (using the actual number of days in that month), and similarly for months.

Kindergarten eligibility

A child is eligible for kindergarten in a given school year if they turn 5 on or before the state's cutoff date that year. The cutoff date is configurable in the calculator (default: September 1). If the child's 5th birthday falls on the cutoff date, they are eligible — the rule is "on or before."

February 29 birthdays

In non-leap years, a February 29 birthday is treated as March 1 for eligibility comparisons. This is the most common legal interpretation and means a Feb 29 child turning 5 in a non-leap year is considered to turn 5 on March 1 of that year. Since most cutoff dates (Sep 1, Aug 1, Oct 1) fall after March 1, these children are typically eligible for kindergarten in the expected year.

Current grade level

The current school year is determined by today's date: if today's month is September or later, the current school year started this calendar year; otherwise it started last year. The current grade is then: currentSchoolYear - kindergartenYear, where 0 = Kindergarten, 1 = Grade 1, and so on through 12 = Grade 12. Values below −1 show "Not yet school age"; values above 12 show "Graduated."

Age at school start

Age at the start of each school year is calculated relative to September 1 of that year, which is the conventional first-day-of-school anchor regardless of the state cutoff date. The timeline shows this age for every school year from kindergarten through Grade 12.

Limitations

Cutoff dates in the calculator and in the state reference table are based on publicly available state regulations. Individual school districts may set their own earlier cutoff or grant early-entry exceptions. Always confirm eligibility with your local school district before enrollment. This tool is for planning purposes only and is not a substitute for official district communication.