WASHINGTON — The early 2020 Democratic fundraising battle has new benchmarks — $18 million, $12 million and $7 million.

That's how much Sens. Bernie Sanders, I-Vt., Kamala Harris, D-Calif., and Mayor Pete Buttigieg of South Bend, Indiana, have raised, respectively, in the first quarter of 2019, according to their campaigns — the only ones so far to announce their hauls ahead of the April 15 deadline for candidates to file reports with the Federal Election Commission.

Fundraising is a critical test of strength, but it's difficult to know how to even assess candidates' money these days, since the party has never had a crowded presidential field like this in the era of small-dollar online donations.

For instance, every candidate to release their numbers so far has posted significantly less than the $25 million that Barack Obama and the $26 million that Hillary Clinton raised back in the first quarter of 2007, the first round of their 2008 primary battle.

That was the last contested Democratic primary with a large field, and even John Edwards raised $14 million that quarter, topping Harris' number today, while former New Mexico Gov. Bill Richardson raised $6 million, on par with Buttigieg's impressive figure.

But those were the days when contribution bundlers were king and candidates spent their days shuffling from one fancy fundraiser to another, sometimes packing in two or three a day. Some of that still happens today, but it's largely fallen out of favor as candidates look to prove grassroots strength by raising money online from a large number of people.

It's also tough to compare candidates' hauls head-to-head since they entered the race at different times, giving some of them more time to raise money. Comparing candidates' dollars-per-day rate can be a better apples-to-apples comparison.

Harris entered the race relatively early, in January, raising $171,428 per day since then. Buttigieg formed his exploratory committee around the same time and took in $102,941 per day. Sanders, meanwhile, announced about a month after both of them, giving him a $443,902-per-day rate.

Sanders has the highest expectations of any candidate, since he has run nationally before and proved the prowess of his massive email fundraising list in 2016.

But he didn't blow his past performance out of the water, despite being much better known than he was four years ago, when he raised $15.3 million in his first quarter of the contest. Only about 20 percent of his donors are new this time around, according to his campaign.

Still, Sanders' operation remains formidable: 525,000 individual contributors and a total of $28 million in the bank, thanks to existing funds the senator had raised in previous election campaigns.

"We're building a campaign to win and we're planning to win from the outset," Sanders campaign manager Faiz Shakir told reporters on a press call Tuesday.

Harris appears to have raised more of her money from larger donors, with an average donation of $55 compared to Sanders’ roughly $20, and pulling in only $6 million online — less than half of her total raised.

Still, that's a lot of money online for someone who has not run for president before, thanks in part to her campaign's massive early investment in digital advertising, which helped her build a donor base of 138,000 people.

"A nationwide network of hundreds of thousands of grassroots supporters has stepped up to lay the foundation for a winning campaign," Harris campaign manager Juan Rodriguez said in a statement. "We're excited by the support we’re already seeing."

Buttigieg had the most surprising show of strength so far, considering he's the mayor of a small city who was almost entirely unknown nationally until weeks ago.

At 158,550 donors, his donor base is already larger than Harris' and his average contribution size is smaller, at around $36.

Overall, some Democratic insiders say the numbers might come in lower than expected for all candidates as donors wait to commit in the crowded field.

Others may wind up supporting multiple candidates.

For instance, Susie Buell, a major San Francisco donor who is close with the Clintons, told NBC News she wanted to hold a fundraiser for Buttigieg even though she's committed to Harris in the long run.

"I am fully supporting and dedicated to Kamala but I feel strongly that mayor Pete has a voice that must be heard. We need to be reassured that we Democrats have outstanding candidates and are welcoming the primary pageant," Buell said in an email.

Campaigns are now waiting anxiously to see what former Rep. Beto O'Rourke reports.

He raised the most money of any known candidate on his first day in the race, $6.1 million.