IRS website - https://www.irs.gov/charities-non-profits/charitable-organizations/charitable-contribution-deductions
In general, contributions to charitable organizations may be deducted up to 50 percent of adjusted gross income computed without regard to net operating loss carrybacks. Contributions to certain private foundations, veterans organizations, fraternal societies, and cemetery organizations are limited to 30 percent adjusted gross income (computed without regard to net operating loss carrybacks), however