Many billionaires give some of their money to charity, but some give a lot of their money to charity.

Created by Berkshire Hathaway CEO Warren Buffett and Bill and Melinda Gates, the Giving Pledge invites the wealthiest people in the world to pledge more than half of their wealth to charitable causes either during their lives or in their wills. As of June, 137 ultra-wealthy individuals and families have joined the effort, with some pledging to allocate more than 99% of their money to philanthropy.

Here are nine billionaire pledgers planning to give away most of their money, and how they plan to give.

Manoj Bhargava, who has promised to donate 90% of his fortune, focuses his charitable work on alleviating human suffering. The founder and CEO of 5-Hour Energy pledged to give more than 90% of his wealth away to charity. Much of his philanthropy aims to alleviate human suffering. His foundation has adopted over 400 projects so far, including bettering schools and hospitals, and advancing women's career education in rural India. Another area of interest: the environment. The foundation is trying to reduce fossil fuel emissions by 50% and clean harmful chemicals from coal.

Sara Blakely attends the 2015 Forbes Women's Summit: Transforming The Rules Of Engagement on June 10, 2015 in New York City. Daniel Zuchnik—WireImage/Getty Images Sara Blakely has made it her life's work to help women. Spanx founder Sara Blakely joined the Giving Pledge to "make the world a better place ... one woman at a time." Her efforts start with a program called Leg-UP, which gives other female entrepreneurs the opportunity to feature their products for free in the Spanx catalog. Blakely has also helped women finance their college educations, funded entrepreneurship programs in girls' schools, and donated $1 million to Oprah's Leadership Academy for girls in South Africa.

Warren Buffett speaks onstage during Fortune's Most Powerful Women Summit on Oct. 13, 2015 in Washington, D.C. Paul Morigi— Getty Images Warren Buffett pledged to give away more than 99% of his riches and has already donated over $21.5 billion. Berkshire Hathaway CEO Warren Buffett is no stranger to philanthropy, having created the Giving Pledge with Bill and Melinda Gates and pledging more than 99% of his own wealth to charitable causes during his lifetime or upon his death. He's already given away $21.5 billion , according to Wealth-X. "To date," he writes in his pledge letter, "about 20% of my shares [in Berkshire Hathaway stock] have been distributed" to various charities. His gift this summer amounted to $2.8 billion — the second year in a row he's given this amount. Buffett will continue to distribute another 4% of his stock every year.

Precious and Patrice Motsepe at the launch of the African edition of Forbes Magazine on Sept. 28, 2011 in Johannesburg, South Africa. Gallo Images/Getty Images Patrice and Precious Motsepe are aiding marginalized and disadvantaged South Africans. Patrice Motsepe, founder of the mining company African Rainbow Minerals and South Africa's first and so far only black billionaire, and his wife Precious are trying to eliminate disparity in South Africa by helping less fortunate South Africans become independent and self-supporting. In 1999, the Motsepes created the Motsepe Foundation and are putting at least half of their wealth toward creating new jobs, supporting education, and improving the lives of children, the unemployed, and the disabled, among others.

Richard Branson speaks at the Clinton Global Initiative Annual Meeting on Sept. 28, 2015 in New York City. CNBC/NBCU Photo Bank/Getty Images Richard Branson devotes 80% of his time to Virgin Unite, the charitable arm of the Virgin Group. Virgin Group founder Richard Branson has his hands in everything from music to telecommunication to air and space travel — and, as of a decade ago, philanthropy. This year, Virgin's non-profit foundation, Virgin Unite , celebrated 10 years of using entrepreneurship to tackle issues like reducing carbon emissions, environment protection, and conflict resolution. Branson and his wife Joan joined the Giving Pledge in 2013 .

Melinda and Bill Gates backstage at the Broadway musical 'Hamilton' on Oct. 11, 2015 in New York City. Bruce Glikas—Getty Images Bill and Melinda Gates are champions in eradicating preventable diseases and have so far donated $27 billion. The other creators of the Giving Pledge, Microsoft founder Bill Gates and his wife Melinda use their foundation to fund initiatives and programs around the world that support agricultural development, emergency relief, urban poverty, global health, and education. They have already given away more money than anyone else on the planet, donating $27 billion , according to Wealth-X. The Gates' are particularly devoted to fighting diseases that, with treatments like vaccinations, are easily preventable. The foundation delivers vaccinations for diseases like polio and tuberculosis to countries that don't have them.

Azim Premji during an interview on May 18, 2012 in New York. Bloomberg/Getty Images Azim Premji funds teacher training and computer programs to reform public schools in India. The chairman of Indian consulting and IT company Wipro works to reform India's public education system through the Azim Premji Foundation. He's given away $8 billion so far , according to Wealth-X. Some of the nonprofit's initiatives include the Computer Aided Learning program, which is offered in 18 languages, and Azim Premji University, a nonprofit university that trains teachers. Premji joined the Giving Pledge in 2013; before that, he donated 8.7% of his Wipro stock (valued at about $2 billion) to set up his foundation.