It was among the smallest fundraising figures to be disclosed voluntarily by a Democrat so far, with roughly 10 months left before the start of primary voting.
Six candidates have released totals: Vermont Sen. Bernie Sanders said he raised $18.2 million; California Sen. Kamala Harris raised over $12 million; former Rep. Beto O’Rourke raised $9.4 million; and Pete Buttigieg, the mayor of South Bend, Ind., raised $7 million.
Booker outpaced only the political newcomer Andrew Yang, who said he'd raised $1.7 million.
Booker's average online donation was $34, and 82 percent of people had never donated to any of his campaigns before.
The senator announced the figures in an email to supporters.
Booker said Sunday he felt“incredible” about the fundraising haul.
“Money is important, but it is definitely not going to be the barometer with which people make their decisions over who’s going to be the next president of the United States,” Booker said. “And I’m happy that we have the resources we need to be in this race.”
The Associated Press contributed to this report.