Contributions From Individual Donors Circles are sized by the total amount to each candidate. Circles are sized by the amount raised by each candidate.

Who has the most campaign cash on hand? Who spent about as much money as they raised? Who relied heavily on personal loans and past political accounts?

Democratic presidential candidates on Monday provided the first broad look at campaign finances. Early fund-raising is no guarantee of votes in 2020, but it is a barometer of which Democrats are generating interest — not an easy feat in a crowded field.

[Here are the nine biggest takeaways from the 2020 money race so far.]

We crunched the fund-raising numbers for 16 Democrats, and the revelations below are telling about how much money they can invest in staff and events in critical early-voting states. Democrats toward the rear of the pack are at a big disadvantage: Their ability to build campaigns to go the distance will be limited unless they improve their fund-raising.

Bernie Sanders and Kamala Harris have raised the most money from individual donors.

Senator Bernie Sanders entered the race with a huge network of online donors from his 2016 presidential bid. Senator Kamala Harris also showed her fund-raising strength, as did former Representative Beto O’Rourke, who raised a mountain of cash in his unsuccessful Senate bid last year.

Total Raised From Individual Contributions (in millions) + Show all candidates

Elizabeth Warren and Kirsten Gillibrand transferred huge sums from their Senate campaigns.

Several candidates supplemented their presidential fund-raising by transferring money raised in past federal races. Legally, money can be transferred only from federal campaigns, giving members of Congress an advantage over candidates who are mayors or governors, or those who have never held federal office. Candidates can also contribute their own money.

Transfers and Candidate Contributions (in millions) Note: Mr. Sanders ended the quarter with roughly $11 million still available to be transferred, his campaign said. Representative Tulsi Gabbard’s transfer amount excludes a redundant transaction made for compliance reasons. Candidate contributions exclude amounts under $10,000.

Sanders also has the most cash in the bank.

The first nominating contests are not until February 2020, so campaigns need to be able to pay their bills for many months to stay afloat. Cash on hand includes loans from candidates and transfers from their previous committees.

Cash on Hand (in millions) + Show all candidates Note: Figures are as of March 31.

Many Democratic candidates are relying heavily on small donors.

Mr. Sanders is counting on small donations to fuel his presidential bid, as is Ms. Warren, who has sworn off holding high-dollar fund-raisers. Ms. Harris has a strong base of online donors, but she has also raised significant sums from traditional donors. Some candidates, such as Ms. Gillibrand, Senator Cory Booker and former Gov. John Hickenlooper, relied heavily on larger donations.

Percentage of Money From Donors Giving $200 or Less + Show all candidates

Warren has spent about as much as she has raised.

The new spending data offers a glimpse into how candidates are prioritizing their resources. Ms. Warren’s sizable spending allowed her to quickly grow her campaign operation and deploy staff members in key states like Iowa, but she burned through almost as much money as she raised in donations.

Total Spent (in millions) + Show all candidates

President Trump’s re-election campaign also reported its fund-raising. The campaign brought in about $30 million in the first three months of 2019 — roughly equal to that of Mr. Sanders and Ms. Harris put together.

[Some candidates have also released their tax returns in recent days. See how they compare.]

Mr. Trump has his own powerful base of small donors. The campaign said its average donation was $34.26.

Online donations of modest amounts will also play an enormous role in the Democratic primary race: many candidates are relying heavily on grass-roots donors to finance their campaigns. Money from small donors is a point of pride, showing that candidates are attracting support from regular people around the country.

Here’s a full look at how the Democratic candidates compare.