Address format matters
Write the box number exactly as the recipient gives it, including any unit designation. A missing box number strands the parcel at the counter waiting for a claim.
Lobby delivery
Shipping to a PO Box, even when the package outgrows it
Any parcel USPS accepts can be sent to a PO Box, and a package too large for a small box does not bounce: the clerk holds it at the counter with a pickup slip, or routes it to a parcel locker. UPS Ground Saver and FedEx Ground Economy can reach a box too, because both hand the last mile to USPS; their faster, non-economy products still want a street address. The rest of this page prices every option that actually reaches the lobby.
Carrier rules stated plainlyBuy the label as a guestTracking to the lobby box
Know the door first
When the destination is a lobby box, the carrier choice narrows before the price comparison starts. The quote below reflects that.
A book bundle bound for a PO Box, quoted 2026-07-27
Our example is the classic PO Box shipment, a 12 × 9 × 6 in box of paperbacks at about 5.5 lb, quoted on Newark, NJ 07102 to Atlanta, GA 30303. The full board is shown for context, but for a PO Box destination the USPS row is the one that matters.
| Carrier | Service | Price | Quoted transit |
|---|---|---|---|
| UPS | Ground Saver | $13.25 | 4 business days |
| USPS | Ground Advantage | $13.29 | 6-7 business days |
| FedEx | Ground Economy | $14.31 | 4-5 business days |
| UPS | Ground | $16.19 | 3-4 business days |
| UPS | 3 Day Select | $19.99 | 3-4 business days |
USPS Ground Advantage quoted $13.29 for a 6-7 business day run, four cents above UPS Ground Saver's $13.25 — and Ground Saver reaches this PO Box too, since it hands the parcel to USPS for final delivery. FedEx Ground Economy, the other PO-Box-capable row, came in a dollar higher at $14.31. UPS Ground and 3 Day Select below them still need a street address.
When the package will not fit the box
The box itself is only the last foot of the journey, so renting the smallest size does not cap what you can receive. Per usps.com/manage/po-boxes.htm, read 2026-08-12, a parcel that outgrows the box goes one of two ways: a slip lands in the box and the package waits at the counter through business hours, or it is placed in a secure parcel locker, including USPS Smart Lockers at select locations, reachable whenever the lobby is. Most PO Box lobbies stay open around the clock.
Speed survives the lobby too. Priority Mail Express delivers to most U.S. addresses and PO Boxes on a 1-3 day window by 6 PM, per usps.com/ship/priority-mail-express.htm read the same day, which makes it the overnight-class option a postal box can accept. Competing overnight products stop at the lobby door, with one narrow carve-out covered in our FedEx to a PO Box guide.
For box holders who want the non-postal carriers anyway, USPS sells an optional Street Addressing add-on that lets the box receive packages from private carriers such as UPS, FedEx, DHL and Amazon, subject to availability at that Post Office. It changes the answer for that one address, not for PO Boxes in general.
Size has a practical ceiling
Oversized parcels for a small lobby box are held behind the counter with a pickup slip instead. Fine for the recipient, but tell them a big one is coming so it does not sit.
The workaround for other carriers
Some post offices offer street addressing for box holders, which lets non-postal carriers deliver there. Only the box holder can confirm their office supports it, so ask before assuming.
PO Box delivery questions
Can UPS or FedEx deliver to a PO Box?
Yes, through one product each. UPS Ground Saver and FedEx Ground Economy both hand the last mile to USPS. UPS's own page, read 2026-08-25, says Ground Saver can deliver to U.S. PO Boxes, APO, FPO and DPO addresses because eligible packages may be handed off to USPS for final delivery. FedEx's shipping FAQ names Ground Economy as its one domestic route to a box number. Their faster, non-economy ground and overnight products still want a street address.
What did the PO Box example cost to ship?
The 5.5 lb book bundle quoted $13.29 with USPS Ground Advantage on 2026-07-27, Newark to Atlanta, quoted at 6-7 business days.
Do PO Box shipments get tracking?
Yes, the same tracking as any street delivery, ending with a scan when the parcel reaches the box or the counter.
How do I address a PO Box parcel?
Recipient name on the first line, the exact box number on the second, then city, state and ZIP. Skip the street address entirely unless the holder tells you they use street addressing.
What happens when a package is too big for a small PO Box?
It still arrives, just not into the box itself. Per usps.com, read 2026-08-12, the clerk either leaves a slip for counter pickup during business hours or places the parcel in a secure locker, including USPS Smart Lockers at select locations.
Can you overnight a package to a PO Box?
Through USPS, yes. Priority Mail Express delivers to most U.S. addresses and PO Boxes, per usps.com read 2026-08-12, with a 1-3 day window and delivery by 6 PM. Overnight products from UPS and FedEx need a street address instead.