Facebook co-founder Mark Zuckerberg announced Tuesday he is a dad and pledged to give away his fortune to make the world a “better place” for baby daughter Maxima and others.

In a letter to Maxima posted on his Facebook page, Zuckerberg and wife Priscilla Chan said they were going to give away 99 percent of their company shares — estimated value $45 billion — during their lives in an effort to make a happy and healthy world.

“Max, we love you and feel a great responsibility to leave the world a better place for you and all children. We wish you a life filled with the same love, hope and joy you give us. We can’t wait to see what you bring to this world,” the letter said.

Zuckerberg will “gift or otherwise direct” nearly all his shares of Facebook stock, or the after-tax proceeds of sales of shares, to further a mission of “advancing human potential and promoting equality” by means of activities for the public good, the California-based social network said in a filing with the US Securities and Exchange Commission.

Zuckerberg “intends to retain his majority voting position in our stock for the foreseeable future,” Facebook said in the SEC filing.

“As you begin the next generation of the Chan Zuckerberg family, we also begin the Chan Zuckerberg Initiative to join people across the world to advance human potential and promote equality for all children in the next generation,” the Facebook chief and his wife said.

“Our initial areas of focus will be personalized learning, curing disease, connecting people and building strong communities.”

Zuckerberg early on added his name to those who have taken a Giving Pledge to dedicate the majority of their wealth to philanthropy.

“My hat’s off to Mark Zuckerberg for making a decision he’ll never regret and making a difference he’ll forever be remembered for,” pledge-signer and former New York City mayor Michael Bloomberg said in an online post.

“The traditional approach to giving –- leaving it to old age or death –- is falling by the wayside, as it should. Mark’s decision shows that when it comes to philanthropy, 30 is the new 70.”

Zuckerberg is 31 years old, while Bloomberg is 73.