Proof & return receipts

Does a deadline count from the postmark or the delivery date?

Updated November 12, 2026 · By the Certified Letter Online team

It depends on the rule that sets the deadline. Federal tax filings, Tax Court petitions and the FTC Cooling-Off Rule count the postmark, so mailing on time is enough. Others, such as a credit card billing-error notice, must be received in time. Certified Mail gives you a postmarked receipt for the mailing date and a delivery record for the receipt date, so it covers both kinds.

When a rule doesn't say, assume receipt is required and mail early. If you are already late, a faster service such as Priority Mail Express can help with receipt deadlines, but it doesn't change the rule.

Examples of deadlines and which date counts
Deadline	Date that counts	Rule
Federal tax return, claim or document	U.S. postmark, if mailed on time and properly addressed	26 U.S.C. 7502
Tax Court petition by mail	Legible USPS postmark within the deadline	U.S. Tax Court
Cancelling a door-to-door sale (FTC Cooling-Off Rule)	Postmark by midnight of the 3rd business day	FTC
Florida timeshare cancellation	Postmark date, if the developer actually receives it	Fla. Stat. 721.10
Credit card billing-error notice	Received within 60 days after the statement was sent	12 CFR 1026.13
Contract notice clauses	Whatever the clause says (mailed, received, or deemed received after X days)	Your contract

Why certified mail is the safe default

Mailing date: the certified receipt carries a USPS postmark. For federal tax documents, the regulation says the postmark on the certified mail sender's receipt is treated as the postmark date (26 CFR 301.7502-1).
Delivery: USPS keeps a delivery record, and a return receipt sends you the signature and date.
Private meters and online postage: the Tax Court warns that private meter marks and postmarks from online postage services do not prove timely mailing. A USPS-postmarked certified receipt does.

If you're up against the deadline

For a receipt deadline, use the fastest service the rule allows (for example Priority Mail Express, or delivering by hand) and keep proof. For a postmark deadline, what matters is getting a USPS postmark on or before the last day.

Our letters are printed and handed to USPS on the same or next business day, so allow for that when your deadline is today. Our mailing date is the USPS acceptance date on your certified receipt.

This guide is general information, not legal advice. For your specific situation, a legal aid office or a licensed attorney in your state can tell you what applies.

Quick answers

Does the postmark date count for a legal deadline?

Only when the rule says so, as with federal tax filings (26 U.S.C. 7502), Tax Court petitions and the FTC Cooling-Off Rule. Otherwise assume the other side must receive it by the deadline.

What if my certified mail doesn't arrive before the deadline?

If the rule counts the mailing date, your postmarked certified receipt proves you were on time. If it counts receipt, you may be late; contact the recipient and keep your receipt and tracking as evidence of when you mailed.

How do I prove I sent a letter before a deadline?

Keep the USPS-postmarked certified receipt (or certificate of mailing), a copy of the letter and the tracking history. See what proof to keep.

What is the fastest way to mail legal documents?

Priority Mail Express is USPS's fastest domestic service; private couriers also offer overnight service. For IRS deadlines only IRS-designated private delivery services get the timely-mailing rule.

What to do next

Get a USPS-postmarked certified receipt for your letter without leaving home: Certified Mail $14.99, with return receipt $17.99.

Mail it certified today

Sources

Checked: November 12, 2026. General information, not legal advice. Fees and rules change: confirm current values at the official links above.