According to Mr Dorsey, the donation represented approximately 28% of his wealth.
He made the announcement on Twitter, writing that the "needs are increasingly urgent".
Mr Dorsey did not lay out exactly where the funds would be sent to help in the battle against Covid-19.
In the US there is a shortage of ventilators and personal protective equipment, and business and individuals are also struggling economically.
Mr Dorsey will use shares he owns in Square to fund the donations which will be distributed through the Start Small Foundation.