Henderson could not say how much money would be saved and redirected because of the closures. She also said the school system has no estimate for the number of employee layoffs expected due to the closures.

The chancellor said in an interview last week, however, that she will push D.C. Council members in early 2013 to grant her authority to approve charter schools, which could then operate in vacant DCPS-owned buildings.

“We don’t have to compete. We can absolutely collaborate,” she said.

Eighteen of the 20 schools would close at the end of this school year. The others — Sharpe Health and Mamie D. Lee, which serve students with disabilities — would move into the former River Terrace Elementary in 2014 after that building is renovated.

Two high schools, Cardozo and Roosevelt, would be converted into secondary schools serving students in grades six through 12. Their feeder middle schools, Shaw at Garnet-Patterson, which serves about 150 students in the U Street corridor, and MacFarland Middle School in Petworth, which is operating at about one-third capacity, would close.

DCPS now enrolls about 45,000 students in 117 buildings; Fairfax County, meanwhile, has about four times as many students in 196 schools.

Henderson said Tuesday that the closures would leave the school system with 101 school buildings with an average enrollment of 432 students, up from 376.

The school system has planned four community meetings for late November and early December to hear community feedback, including on how vacant buildings should be used. In addition, the D.C. Council will hold public hearings on the plan Thursday and Monday.

Henderson said she will listen to public input before making final recommendations to Gray in mid-January.