How To Send USPS Priority Express Mail
To send a package by USPS Priority Mail Express, you pack it in a free Flat Rate envelope or your own box, weigh and measure it, buy postage at a Post Office counter or online with Click-N-Ship, and hand it to USPS at a counter, in a Priority Mail Express collection box, or through a free scheduled pickup. USPS delivers it in 1 to 3 days by 6 PM local time with a money-back guarantee. It is not an overnight service by default, and weekends do not make it one. The steps below cover cost, hand-off, how to find your actual delivery day, and how to claim the refund if USPS misses it.
How fast Priority Mail Express actually is
USPS describes the service on its Priority Mail Express page as 1 to 3 day delivery by 6 PM with a money-back guarantee, to most U.S. addresses and PO Boxes, every day of the year with limited exceptions. Next-day delivery exists, but only between certain origin and destination ZIP Codes and only if you hand the parcel over early enough.
The only reliable way to know whether your parcel will arrive tomorrow is the USPS Service Commitments tool. Enter both ZIP Codes and your mailing date and time, and it returns the scheduled delivery day and whether the money-back guarantee applies. Drop-off times vary by Post Office, so confirm the cutoff at the location you plan to use. Sunday and holiday delivery is available in many major markets for an additional fee, which we cover in is USPS delivery available on weekends. For how the service compares with regular Priority Mail, see what Priority Mail Express covers.
Step 1: Pack it
USPS supplies free Priority Mail Express Flat Rate envelopes in three sizes: the standard Flat Rate Envelope (12 1/2 by 9 1/2 inches), the Legal Flat Rate Envelope (15 by 9 1/2 inches), and the Padded Flat Rate Envelope (12 1/2 by 9 1/2 inches). Anything that fits and weighs up to 70 pounds ships to any state at one price. USPS says free supplies usually arrive with your regular mail within 7 to 10 days, so order them before you need them.
Otherwise, use your own box or envelope for mailable items up to 70 pounds, priced by weight and zone. USPS does not require you to register before using the service.
Step 2: Weigh and measure it
Flat Rate envelopes skip this step. For your own packaging, weigh the parcel and measure its length, width, and height, rounding any fraction up to the next inch. If the box is larger than 1 cubic foot (1,728 cubic inches), USPS applies dimensional weight: multiply length by width by height and divide by 139. If that number is larger than the actual weight, you pay for the dimensional weight instead.
Odd packages also carry nonstandard fees on top of postage, per the USPS Priority Mail Express page:
Package condition | Added fee |
|---|---|
Between 22 and 30 inches long | $4.50 |
More than 30 inches long | $21.00 |
More than 2 cubic feet (3,456 cubic inches) | $35.00 |
Nonstandard shape or material, such as a tube, can, or wooden box | $4.50 |
Flat Rate packaging is exempt from all nonstandard fees. Separately, live animals and perishable items such as food or plants carry a $7.50 handling fee, and hazardous materials carry a $7.50 handling fee.
Step 3: Buy postage
There are three ways to pay, and the price differs between them.
- At a Post Office counter. USPS lists prices starting at $35.65 at a Post Office. The three Flat Rate envelopes cost $35.90, $36.20, and $36.90 at the counter.
- Online with Click-N-Ship. You get USPS Commercial Rates, which are lower than counter prices. The same three Flat Rate envelopes are $31.11, $31.43, and $31.70 online. You need a usps.com account, and you print the label yourself. See what Click-N-Ship is for the walkthrough.
- Through a PC Postage provider. Registered users of a postage platform that prints individual labels also get Commercial Rates.
If you do not have a printer, USPS Label Delivery solves it: for $1.65 per label, USPS prints your Click-N-Ship label and delivers it to you.
Two things to decide at checkout. If you want a signature on file, request the proof of delivery signature record when you buy postage; it is included in the price only if you ask for it then. And buy the label when the parcel is ready to go, because USPS bases the scheduled delivery day on the date and time you say you will mail it. See whether USPS labels expire for the timing.
Step 4: Hand it to USPS
USPS accepts Priority Mail Express at Post Office counters, stations, and branches, at Contract Postal Units, in Priority Mail Express collection boxes, from your carrier, or through a scheduled pickup. Package Pickup is free at your home or office; our guide to scheduling a USPS pickup covers the options.
The hand-off time is the part most people get wrong. USPS states that the time of day an item is accepted or dropped off affects whether it arrives in 1 to 3 days by 6 PM, and drop-off deadlines vary by Post Office. If you need next-day delivery, run the Service Commitments lookup first and get the parcel to a location that meets the deadline. Keep the receipt or your copy of the label; it carries the guaranteed delivery date and time, and you need it to file a refund.
Step 5: Track it
USPS Tracking is included, and most shipments include up to $100 of insurance at no extra charge, as long as the parcel carries an applicable USPS shipping label. For contents worth more, USPS says additional insurance may be available for purchase.
Can you send Priority Mail Express to a PO Box?
Yes. USPS delivers Priority Mail Express to most U.S. addresses and PO Boxes. One detail matters for the guarantee: for a PO Box address, an "Arrival at Pickup Point" scan counts as meeting the delivery commitment. The parcel is on time once it is available at the box, even if the box holder collects it days later.
If it arrives late: how the refund works
The money-back guarantee refunds the postage, plus the Sunday or holiday premium if you paid one, when the parcel is not delivered or delivery is not attempted by the guaranteed date and time on your receipt. The rules come from the USPS Priority Mail Express FAQ and the USPS Priority Mail Express page.
- Who can file. Only the sender.
- When to file. No sooner than 2 days and no later than 30 days after the mailing date if you bought no extra service. With an extra service, the window is 30 to 60 days after mailing.
- How to file. File online at usps.com, or take the mailing receipt or your customer copy of the label to any Post Office and complete PS Form 3533.
- If USPS says no. Online denials can be appealed online within 30 days of the denial.
- What counts as on time. An "Attempted delivery" scan meets the commitment even if nobody was there to sign. So does an "Arrival at Pickup Point" scan for a PO Box and a "Forwarded" scan when the address on the label was wrong. USPS notes this list is not complete.
There are exclusions. Since August 1, 2023, USPS no longer processes guaranteed-service refunds for Priority Mail Express items addressed to or from Alaska or Hawaii, although refund requests for loss are still processed. Postage is not refunded when the delay came from an incorrect address or ZIP Code, a strike, a law-enforcement hold, or other causes USPS says were beyond its control, or when a parcel of live animals or hazardous materials was delivered within 3 days of mailing.
A late parcel and a missing parcel are different problems. If tracking has stopped entirely, follow what to do when USPS loses your package instead.
When the counter trip stops making sense
Once you are buying labels and booking pickups every day, the time adds up. Simpl's flat-rate ecommerce order fulfillment includes pick, pack, postage, and packaging, ships with UPS, USPS, and FedEx, and ships orders received before 12pm CT the same day. See how ecommerce fulfillment works at Simpl.