Cash contributions made to charity in 2018 and beyond are deductible up to 60% of adjusted gross income. If you have a carryover of a cash contribution because of the application of the 50% limit that applied prior to 2018, you can use the carryover in 2018 through 2025 up to the 60% limit.
A 12-month period ending on the last day of any month other than December. Partnerships, S corporations, and personal service corporations are limited in their choice of fiscal years and face special restrictions.