Mayor Bill de Blasio has proposed funding more than 38,000 new public school seats in his preliminary budget for the coming fiscal year.

At a City Hall news conference, de Blasio unveiled an $84.7 billion budget for the fiscal year beginning July 1 that also would hold a record amount of money in reserve to offset possible federal funding cuts.

UFT President Michael Mulgrew said he hopes the additional classroom seats will further the union’s goal of lowering class size.

“In New York City, the only thing that regulates class size now is our union’s contract,” he said. “It’s just common sense: Fewer students in a classroom means more time a teacher has with each student and that makes a difference. We’re looking forward to seeing how this plan will help.”

The mayor set aside an additional $495 million in the capital budget to fully fund 38,487 seats to ease overcrowding.

The budget also allocates $6.3 million for 200 new school crossing guards and 100 supervisors; $16.2 million for upgrades and improvements to the Special Education Student Information System (SESIS); $14.3 million to expand the Summer in the City summer school program; $8.4 million for DOE Data Center upgrades; $8 million for broadband upgrades; and $4.6 million for per session special education services.

“Mayor de Blasio is investing in education while still being financially cautious because of what may be coming out of Washington, D.C.,” Mulgrew said.

While the budget includes an increase of about $71 million for homeless shelters, Mulgrew said of “deep concern” to the UFT is a $10 million cut for services to support a growing population of homeless students.

Also reflected in the financial plan is the proposed closure or consolidation of 11 schools in the mayor’s School Renewal Program.

The proposals are now subject to the annual back-and-forth among City Council members, City Hall officials and advocates. The final city budget is due on July 1.