Once postage is on the box, USPS says any drop-off method works, mailbox included. Loose stamps are held to a stricter size rule.
The four moves, in order
- Decide Priority Mail is the tier you want. USPS states Priority Mail at 2-3 days with a 70 lb ceiling, read 2026-08-28, the same weight ceiling Ground Advantage carries. If the date is flexible, Ground Advantage is usually the cheaper pick for the same box; our Ground Advantage against Priority Mail guide prices both across several routes.
- Box it. A sturdy box already in the house works fine. USPS also lists Priority Mail and Priority Mail Express boxes and envelopes on store.usps.com, read 2026-08-28, with no charge for the packaging. The condition: “All USPS-produced packaging (including Flat-Rate packaging) must be used only for the applicable product,” per DMM 601.6.1, pe.usps.com, read 2026-08-28. Pack a cheaper service into one of these boxes and the Priority Mail price still applies.
- Weigh and measure the packed box. 70 lb is the ceiling, and combined length plus girth has to stay under 108 inches, per usps.com, read 2026-08-28, tighter than the 130-inch figure the same page states for USPS packages in general. A flat rate box sidesteps the scale inside its own size class; our flat rate envelope page has the fixed prices.
- Buy the label. Enter the packed box and both ZIP codes into a shipping calculator and pay as a guest; the label prints from any browser with a tracking number attached before checkout closes. Without a printer at home, the Label Broker route turns a QR code into a paper label at a participating counter.
- Hand it off. A printed label clears the counter requirement entirely; see the drop-off rule below before assuming a trip is needed.
Where the counter stops being required
“If you printed the postage using Click-N-Ship or at a USPS kiosk, you can use any method to drop off your packages.” usps.com, How to Prepare & Send a Package, read 2026-08-28.
The same logic carries over to a label bought through any online shipping checkout: postage is postage once it is printed, and nothing at the mailbox distinguishes where it came from. A package paid for with loose stamps does not get the same latitude. Per the same page, stamped mail only clears a mailbox or collection box under half an inch thick and under 10 oz; past that it goes to a Post Office counter regardless of the class printed on it.
Scheduling a pickup is the other option USPS lists on that page: a carrier collects the box during the regular delivery run at no added charge, or on a paid visit booked through Pickup on Demand, read 2026-08-28.
What we paid, next to what USPS lists
Two figures are worth keeping apart: USPS's own published counter rate for a box, and the total a checkout charges for the same box with tracking and payment already handled. Through our checkout on 2026-08-28, that 1 lb box priced at $14.49 on Priority Mail against a $13.05 counter rate, and $9.91 on Ground Advantage against a $10.95 counter rate.
| Service | Post Office price | Checkout total | Quoted window |
|---|---|---|---|
| Ground Advantage | $10.95 | $9.91 | 3-4 business days |
| Priority Mail | $13.05 | $14.49 | 3-4 business days |
The comparison is not symmetric: our Ground Advantage total sat under USPS's own counter rate, while our Priority Mail total sat a little above it. Both are real numbers from the same request, so check your own box rather than assuming a checkout price always beats the counter.
One more honest note: USPS's own headline for Priority Mail reads 2-3 days, read 2026-08-28. On this route, Ground Advantage and Priority Mail came back with the identical 3-4 business day window in the same request. That is what this route returned on this day, not a claim about every route; a shorter zone or a heavier box can easily separate the two. A fuller weight ladder sits on our Priority Mail rates page.
Three things worth knowing before you pay
Express is a different product
Priority Mail Express is USPS's faster, pricier sibling, with its own page and its own price ladder. If a couple of days will not do, price that service directly instead of assuming this one stretches to cover it; see our Priority Mail Express cost breakdown.
A pickup can replace the trip
A carrier will collect a Priority Mail box from home during the regular delivery run at no added charge, per usps.com, read 2026-08-28, which is often faster than finding a collection box.
Flat rate rewards a full box
A flat rate box charges the same price up to 70 lb regardless of what is inside, and a light box in a flat rate container usually loses to the weighed price. Our flat rate envelope page prices the full lineup.
Where these rules come from
- USPS, How to Prepare & Send a Package — the Click-N-Ship and kiosk drop-off line, the stamped-mail half-inch and 10 oz thresholds, the free carrier pickup against paid Pickup on Demand, and both size ceilings: “Packages can't be larger than 130″ total length + girth. For Priority Mail and Priority Mail Express packages, total length + girth must be less than 108″.” Read 2026-08-28.
- USPS, Priority Mail — the 2-3 day headline and the 70 lb ceiling. Read 2026-08-28.
- USPS, Free Shipping Supplies — the Priority Mail and Priority Mail Express boxes and envelopes the Postal Store ships with no price against them. Read 2026-08-28.
- USPS, DMM 601.6.1, USPS-Produced Packaging — the rule that USPS-produced packaging is used only for its own product. Read 2026-08-28.
- Our own checkout, one request covering both services on a 1 lb box measuring 10 × 8 × 2 in, Berkeley Heights NJ 07922 to Chicago IL 60601 — the $14.49 and $9.91 totals and the counter rates beside them. Captured 2026-08-28.
USPS revises its own published pages and its prices without notice. Every line above is dated because of it; requote the box and re-read the rule before relying on either.
Common questions
How do I send something Priority Mail?
Box it, weigh and measure the packed box, buy a label online or at a Post Office counter, then hand it off. A label bought online skips the counter for almost any size; a package paid for with loose stamps only skips it when it is under half an inch thick and under 10 oz, per usps.com, read 2026-08-28.
Do I need a special Priority Mail box?
No. Any sturdy box works, priced by weight and zone. USPS also lists Priority Mail and Priority Mail Express boxes and envelopes on store.usps.com, read 2026-08-28, at no charge for the box itself, but that packaging is built for Priority pricing specifically. Under DMM 601.6.1, using it for a different service still bills at the Priority Mail price.
Can I put a Priority Mail package in my mailbox?
Yes, once the postage is printed. Per usps.com, read 2026-08-28, a package with postage printed online or at a kiosk can use any drop-off method, mailbox included. A package paid for with loose stamps is held to a stricter rule: under half an inch thick and under 10 oz, or it goes to the counter.
How big can a Priority Mail package be?
70 lb, with combined length and girth under 108 inches, per usps.com, read 2026-08-28. That is a tighter ceiling than the 130-inch figure the same page gives for USPS packages generally.
How much does it cost to send something Priority Mail?
Through our checkout, a 1 lb box at 10 x 8 x 2 in priced at $14.49 for Priority Mail from Berkeley Heights, NJ to Chicago, IL on 2026-08-28, next to USPS's own published counter rate of $13.05 for the identical box. The same box on Ground Advantage priced at $9.91, against a $10.95 counter rate.
Did Priority Mail beat Ground Advantage on the route quoted here?
USPS's own headline claim is 2-3 days, read 2026-08-28. On the one route we quoted that same day, Priority and Ground Advantage returned the identical 3-4 business day window, a real result on that route, not a rule. Check your own route before paying the difference.