Legacy IRA Act This bill amends the Internal Revenue Code to expand the tax exclusion for distributions from individual retirement accounts (IRAs) for charitable purposes. The bill increases from $100,000 to $400,000 the annual limit on the aggregate amount of distributions for charitable purposes that may be excluded from the gross income of a taxpayer. The bill permits tax-free distributions from IRAs to a split-interest entity until December 31, 2021. A split-interest entity is exclusively funded by charitable distributions and includes: a charitable remainder annuity trust, a charitable remainder unitrust, or a charitable gift annuity. A charitable gift annuity must commence fixed payments of at least 5% no later than one year from the date of funding. A distribution to a split-interest entity may only be treated as a qualified charitable distribution if: (1) no person holds an income interest in the entity other than the individual for whose benefit the account is maintained, the spouse of such individual, or both; and (2) the income interest in the entity is nonassignable. The bill limits the exclusion annually to: $100,000 for distributions to charitable organizations, and $400,000 for distributions to split-interest entities. Tax-free distributions to a split-interest entity may be made when the account beneficiary attains age 65. (Under current law, the beneficiary must attain the age of 70-1/2 for IRA distributions to a charitable organization.)