According to the IRS, a written acknowledgment from the recipient charity is *required* for any charitable donation of $250 or more to be deductible.
For a donation of less than that amount, proof of payment (a receipt, cancelled check, credit card charge, whatever…) should suffice.
Read all about it here in IRS’s Publication 1771:
It’s only seven pages long!!!
- This reply was modified 3 years ago by snargle.