Washington area nonprofits are gearing up for a regionwide fundraising appeal called “Do More 24” that kicks off Thursday.

The 24-hour campaign, organized by the United Way of the National Capital Area, is urging donors to go online to contribute at least $10 to their favorite charity. The nonprofits can win additional prize money for achievements such as securing the most donors and using creative social media techniques.

The United Way hopes to raise at least $2 million for nearly 1,000 participating charities, roughly matching the dollar amount residents pledged during a similar 2011 fundraising drive called “Give to the Max.”

As much as the money is important, organizers say such events can help charities reach new donors. Many are pairing their online efforts with offline, physical events.

District-based service agency Mary’s Center said one of the contributors who reached out during the 2011 campaign later gave the nonprofit a $50,000 donation. So this year, the health center is going all out to spread the word and attract more new givers.

The Do More 24 logo is front-and-center on the Mary’s Center Web site, and staff members have sent thousands of e-mails to supporters, alerting them to the campaign and inviting them to a reception that day.

“When you’re in fundraising, you have to take advantage of every single opportunity, because if we don’t, somebody else will,” said the group’s development director, Rebecca Diamond.

Sasha Bruce Youthwork, an organization that serves at-risk youth and their families, is trying to draw attention to its campaign by planning a live painting demonstration in Eastern Market and offering passersby an opportunity to paint, play games or do sidewalk chalk art.

“This is hugely important for us right now,” said James Beck, the group’s development director. He said that as a result of cuts in city funding, the group lost $430,000, which supports its emergency shelter for homeless youth.

Little Lights Urban Ministries is hoping to replicate the success it had during the Give to the Max event. The group won the competition for securing the most donors. It took home nearly $80,000 from 729 donors, which covered a previous $60,000 cut in foundation grants. This year, the group is recruiting “rally captains” who are charged to persuade at least 24 people to donate. In addition to calling the 3,000 people on its contact list, the staff is also planning an event at a coffee shop.

“This is going to be a very busy week,” said Stephen Saunders, development director at Little Lights.

To participate, nonprofits must set up a page on the Do More 24 Web site, at no cost to the charity. United Way has also held boot camps to help groups set up their page and publicize.

United Way is charging a 4.9 percent fee on donations to cover bank-processing costs and administrative expenses.

Officials at the United Way said the organization spent $350,000 to organize the event.

Online giving is fast becoming the donation vehicle of choice for many, particularly younger donors who have grown accustomed to sites such as DonorsChoose, Causes, Network for Good, Fundly, Global Giving and Crowdrise. An annual online day-of-giving event called “#Giving Tuesday,” which urges people to give to charity on the Tuesday after Thanksgiving, raised $10 million last year.

Give to the Max day was organized by an online fundraising company called Razoo, which has offices in the District and San Francisco, where its senior leadership is located.

The United Way wanted to “scale this and build our own platform,” said Michael Altman, spokesman for the United Way. He said that a partnership with Razoo wasn’t ideal because the private company held rights to the campaign data and is “not local.”

Lesley Mansford, chief executive of Razoo, said in an e-mail: “Though not involved this year, we wish the nonprofits the very best, and support anything that raises awareness and funds for the nonprofits of the region.”