Last night President Joe Biden laid out his plan for $1.8 trillion in spending to support American families. It includes proposals to provide universal free preschool and make child care more affordable. The average cost of child care nationally tops $8,000 a year — more than in-state tuition for public universities in many states. Here’s a breakdown of that cost.

First, there’s the overhead. Child care is heavily regulated, and states often have strict requirements for physical spaces, according to Shannon Heck with Imprints Cares, a nonprofit in Winston-Salem, North Carolina, that offers early education and after-school services.

“It does tell you specifically how much square footage per child you need,” Heck said. “Obviously, there are safety considerations … entrance and exits, and windows and outlets.”

There’s also liability insurance and licensing fees, but by far the biggest cost is labor, almost 80% of Imprints Cares’ budget.

Wages among child care providers are generally low — about $11 or $12 an hour, Heck said — but they add up for child care centers because the work is labor intensive. Regulations vary by state, but facilities usually need at least one caregiver for every four infants. That ratio might be 1 to 6 for older toddlers, but Paula Drew, co-director of Wisconsin Early Education Shared Services Network, said even that’s hard.

“It felt really, really intense to care for six 2-year-olds on my own, because they are moving, they are learning to speak, they are learning to potty train, they are learning so much about the world,” she said.

The difficulty and importance of the work make it all the more troubling that it’s so poorly paid, said Taryn Morrissey, associate professor of public administration and policy at American University.

“Child care providers are disproportionately women, disproportionately women of color, and they make near-poverty wages,” she said. “Few have health insurance through their employers, relatively few have other sorts of benefits.”

Research by the Center for the Study of Child Care Employment at University of California, Berkeley, found almost half of care giving workers in California had such low wages they relied on some form of public assistance.

“These early educators really are the architects of young children’s brains. That’s hard work,” said Lea Austin, director of the UC Berkeley center. “And we have a circumstance now where that work is incredibly undervalued, underpaid,” even as families struggle to afford the care.

The low wages also result in high turnover, which adds costs for recruiting and training new workers more frequently.