Andy Yung, a prekindergarten teacher in Queens, is adept at raising money online for ambitious classroom projects, but even he sometimes pays for supplies out of pocket.

And he has company. According to a federal Department of Education survey released on Tuesday, 94 percent of public school teachers in the United States reported paying for supplies without reimbursement in the school year that straddled 2014 and 2015.

It made little difference whether they taught in cities, suburbs or rural areas, or whether or not their students were poor — virtually every public school teacher said they had used their own money for their classrooms.

“It’s almost expected, especially in the summer months creeping up into September,” Mr. Yung said. “It’s just something we kind of naturally do.”