Parents whose children turn four this year may start applying for pre-kindergarten this week. Applications are available online now and the Education Department will host pre-K info sessions in all five boroughs this week, beginning in Queens tonight. Applications are due April 5.

Pre-K programs are housed in public schools or at local child care centers and community organizations, and are either half day (2.5 hours), or full day, (6 hours and 20 minutes.) The state mandates that each pre-k class may have a maximum of 18 students with two teachers. 

Applying for pre-K gives parents a first taste of New York City's competitive public school admissions process. Any child who was born in 2009 may apply, but admission is not guaranteed: Last year, 30 percent of the kids who applied for pre-K didn't land seats in DOE programs. 

The DOE published last year's acceptance numbers in its 2013 pre-K directory.This handy DNAinfo chart breaks down 2012 acceptance numbers by district and by school. Just remember the numbers include all children who applied, including those from outside of the school's zone, district and borough. Your chances are better if you live in the zone.

This year, the DOE added 4000 full-day pre-k seats to its fall 2013 roster, but there are still too few seats to meet demand. 

The DOE has centralized pre-K admissions process (unlike kindergarten admission, which is mostly handled by individual schools.) For pre-K, parents fill out applications ranking their top 12 choices, which they may submit online or at DOE enrollment offices between March 4 and April 5. The DOE sorts applications with a computer program that ranks choices and assigns children to pre-K programs, with acceptance letters going out in in early June, according to the DOE.

Pre-K admissions process is not "first-come, first-served," meaning parents who submit applications earlier are not more likely to land a seat than parents who apply closer to the April 5 deadline.

After the application process closes, spots will be randomly assigned according to a list of 10 priorities, with first dibs going to families who live in the zone and have a sibling enrolled in the school. Children may apply to any pre-K program citywide, but chances of acceptance are increased based on proximity, as the school's zone, district or borough are other factors the DOE's alogrithm considers when assigning pre-K seats.

Pre-K differs from kindergarten in a few other notable ways: the DOE does not provide transportation, so parents should keep travel arrangements in mind for all the schools they rank. Also, the DOE does not guarantee that all special needs will be met no matter which pre-K program you enroll in. Parents of children with special needs should check with their local Committee on Special Education (listed on page 3 of the pre-K directory) before applying to pre-K. 

Something else to consider: this year, for the first time, students already enrolled in a school's pre-k will have preference for that school's kindergarten over other out of zone kids who apply. But, the most popular schools do fill their seats with kids from the zone.

Community Based Organizations (CBOs), such as Y's, preschools and other childcare centers, also provide thousands of pre-K seats that are free and available to the public each year. Those programs are listed in the pre-K directory, starting on page 22. The DOE does not manage CBO admissions, and there is no centrally organized place to apply for these programs. You must call the CBO for specific program information and to apply.

Admission to CBO programs is usually rolling, though policies vary. At a pre-K admissions training session last week, the DOE said that CBOs usually have 1000s of empty seats for pre-K, and suggested CBOs as an alternative for parents who couldn't get a spot in public schools. But most CBOs only provide half-day pre-K, so will not meet the needs of parents who are looking for full-day programs (though some programs can be extended to full-day for a fee).