The city education department is recommending an overhaul of its gifted and talented programs that is likely to change both who can get into the programs and what the programs look like.

Admissions criteria at the gifted and talented programs, which enroll about 5% of the city’s elementary school students, vary widely: some are exclusive while others let in 50% of applicants or more.

Calling that system irrational, the city schools chancellor, Joel Klein, said today he plans to streamline admissions to the programs this year, asking all children to take a single set of tests and guaranteeing a spot to any child who scores in the top 5% nationwide.

Mr. Klein said the change will bring a clearer definition of giftedness to the programs and also open access to more students.

The current process of admissions pits children against one another for a fixed number of seats in each district, with spots going to top scorers — no matter how high or low those children have scored.

The city will also offer free, in-school eligibility testing for students whose parents request it, whereas in the past, parents had to pay private testing agencies. Access will widen even further next year, when school officials plan to give a “screen” test to every kindergartener in New York, whether a parent requests it or not.

“I’m convinced there are gifted and talented children in all communities,” Mr. Klein said. “We need to make sure they avail themselves of the opportunities.”

Mr. Klein predicted that the effect on programs would vary by district: those with lower standards of entry might see their enrollment shrink, while those enforcing stricter criteria could expect to offer more seats.

Students now enrolled in gifted programs will not be affected by the change, Mr. Klein said.