If you’re claiming the itemized deduction instead of the standard deduct, any charitable contributions that exceed 50% of your adjusted gross income (AGI) for that year can be carried forward and used as a deduction in another tax year. Your AGI is the amount listed on Form 1040 line 37. The carryover amount must be deducted within five years or it will be lost.
For example, you made $11,000 in donations during 2017 and your AGI is $20,000. You can only deduct $10,000 for charitable contributions on your 2017 tax return. The remaining $1,000 can be used as a charitable contribution deduction on your 2018 tax return. You have until 2022 to use up all the contribution carryover or it will be lost.
Important: When you use carryover contributions in a future year, you can’t deduct them until you first deduct all the contributions from the current tax year.