During his campaign, Trump promised he’d get Mexico to foot the bill, saying in April of last year that the United States’ neighbor to the south could make a “one-time payment of $5-10 billion to ensure that $24 billion continues to flow into their country year after year.”

But last July, research group Bernstein estimated a different figure, and it’s a lot more than the President predicted. Minus labor and land acquisition costs, analysts there found that the materials needed to build a 40-foot-tall, 7-foot-deep, 10-inch-thick, and 1,000-mile-long wall between the U.S. and Mexico would cost $15 billion.

While President Trump has yet to release construction specs for his wall, Bernstein made its estimate based on both his statements about its possible dimensions and the group’s own assumptions. Fortune checked with Bernstein to see if their estimate still stands, and they told us it does.

Add in labor and land acquisition, and the cost of the wall could reach $25 billion, according to Bernstein. And depending on its height, costs for concrete and cement could reach $1 billion and $330 million, respectively. Flooding and rough terrain could also raise the price tag.

According to U.S. Government Accountability Office data cited by Bernstein, building the “easiest” sections of the existing 653 miles of fencing ran between $2.8 million and $3.9 million per mile as part of the $7 billion that’s been spent since 2001.