If you’re in the US and dropping checks in the mail today, I would not rely on the assumption that they would be postmarked today. Effective December 24, the postmark date is no longer the date on which mail is deposited with USPS (although it sounds like postmark date may not have been fully reliable even before this policy change).
Under Treasury Regulation 1.170A-1, “[t]he unconditional delivery or mailing of a check which subsequently clears in due course will constitute an effective contribution on the date of delivery or mailing.” I have usually filmed myself dropping checks into the USPS mailbox for this reason, and will do so with my wife’s charitable contributions this year (mine are already done). The safer alternative, especially if large sums are involved, would be to take the mailpiece to a post office and have a manual postmark applied by the person behind the counter (or send via certified mail).
If you’re in the US and dropping checks in the mail today, I would not rely on the assumption that they would be postmarked today. Effective December 24, the postmark date is no longer the date on which mail is deposited with USPS (although it sounds like postmark date may not have been fully reliable even before this policy change).
Under Treasury Regulation 1.170A-1, “[t]he unconditional delivery or mailing of a check which subsequently clears in due course will constitute an effective contribution on the date of delivery or
mailing.” I have usually filmed myself dropping checks into the USPS mailbox for this reason, and will do so with my wife’s charitable contributions this year (mine are already done). The safer alternative, especially if large sums are involved, would be to take the mailpiece to a post office and have a manual postmark applied by the person behind the counter (or send via certified mail).