President Biden’s re-election campaign said on Sunday that it had raised more than $53 million in February together with the Democratic Party, an influx of cash that is expected to widen the Democrats’ cash advantage in a general-election contest against former President Donald J. Trump.

Biden, the Democratic Party and their shared accounts now have $155 million cash on hand — up from $130 million at the end of January, his campaign said. The campaign credited strong support from small-dollar donors for its February fund-raising.

So far in the race, Biden and the Democrats have built a substantial fund-raising advantage over Trump and the Republican National Committee, which reported around $40 million in cash on hand between them at the end of January. The Trump campaign has not released its February fund-raising figures but has said it also had its strongest month among small donors — topping the $22.3 million raised last August. Trump and the R.N.C. formed a formal joint fund-raising account only last week.

“The fact that we have $155 million in cash on hand — which is 100 per cent going to building out the campaign and focused on the six or seven states that are going to determine the outcome of this election — is just a huge competitive advantage,” Jeffrey Katzenberg, a co-chair of the Biden campaign, said in an interview.