Shipping rates not showing at checkout › USPS rates
Shopify checkout diagnosticsUSPS rates not showing at checkout
You ship from the United States and turned on USPS rates. At checkout, buyers get only Priority Mail, or one option where you expected three, or no USPS rate at all. USPS is the carrier most US Shopify stores start with, and its missing rates usually come down to a few settings that look harmless: the default box, the services you ticked, and where your stock sits.
“Although I have multiple shipping rate options enabled, only one is available to select during checkout.”
That merchant, in a 2022 Shopify Community thread, found the cause with Shopify Support: the default package was a USPS Priority Mail box. Switching to a custom box brought the other rates back. It is the most common USPS trap, and it is documented.
Which USPS rates are you using?
There are two ways to show USPS rates at checkout, and they have different requirements.
- Shopify's built-in USPS rates. Available on all plans for stores with a fulfilment location in the United States. The rates are based on Shopify's own account with USPS.
- Your own USPS account, through third-party carrier-calculated shipping. It needs a US fulfilment location and a plan that includes the feature: Advanced or Plus, or Grow with yearly billing or a monthly fee. Not Basic, not Starter. When you connect, you choose commercial rates (the default, cheaper) or retail rates.
Both appear as a Carrier or app calculated shipping option in a zone of a shipping profile, where you tick the USPS services to offer.
Only one USPS service shows
The default package is a USPS box
Shopify's troubleshooting guide is explicit: if the default box is set to a carrier package, only that carrier's rates display. Its own example is USPS: the Priority Mail flat rate box only works for Priority Mail options, so if Priority Mail rates are not active, no rates display at all. A USPS box as default can therefore give you “only Priority Mail” or “nothing”, depending on what you ticked.
Fix: add a custom box with the outside dimensions of what you really ship, and set it as the default package in Settings → Shipping and delivery → Packages. Only one default package is used at checkout; a package assigned to a variant overrides it for single-item orders only.
The service you ticked no longer exists
USPS launched Ground Advantage in July 2023 and retired three services with it: USPS Retail Ground, Parcel Select Ground and First-Class Package Service. First-Class Mail still exists, but Shopify describes it as a way to ship large envelopes. So a rate set up years ago around “First-Class Package” for light parcels needs Ground Advantage instead.
Open the USPS option with Edit shipping option, check that Ground Advantage is ticked, and consider Automatically include new services when they become available. The Community thread about a missing First-Class Package option, opened in 2021, got a second report on 9 July 2023, the eve of the Ground Advantage launch. The thread does not say whether that was the cause; it is worth checking first.
The parcel does not fit the service
Each USPS service has its own limits, and a cart outside them gets no rate for that service while others still show. From USPS's own pages:
| Service | Maximum weight | Maximum length + girth |
|---|---|---|
| Ground Advantage | 70 lb | 130 inches |
| Priority Mail | 70 lb | 108 inches |
Shopify's USPS page gives 70 lb and 108 inches combined length and girth as the maximum for domestic shipments. For international services, limits vary by destination country. The weight Shopify sends is the products plus the default package, so check variant weights and units too: a product with no weight is treated as weightless, and a weight typed in the wrong unit can push a cart over a limit.
No USPS rate at all
The stock is not at a physical US location
For rates from Shopify's shipping labels, Shopify requires available stock at a physical location, not an app or custom fulfilment location. More generally, a location must be active, have a valid address and be set to fulfil online orders. A product stocked only at a dropshipping or print-on-demand app's location has no USPS origin.
The USPS rate is not where the product and buyer are
The USPS option lives in one zone of one profile. A product in a custom profile without a USPS option, or a buyer in a zone without one, gets none. More on products in separate profiles.
Your own account, without the plan
If you connected your own USPS account, check that your plan still includes third-party carrier-calculated shipping and that the account still shows under Carrier accounts. Then use Calculate rates on the carrier to see sample rates for a package and an address. Shopify warns they may differ from checkout, but none at all is a clear sign.
The buyer is abroad
Shopify's built-in USPS services for international parcels are First-Class Package International Service, Priority Mail International and Priority Mail Express International. If a zone for another country relies only on USPS, it depends on USPS accepting that parcel for that country. Keep a flat rate for destinations that matter to you.
Military addresses
USPS charges domestic prices for packages to Military Post Offices (APO/FPO/DPO), and says these destinations need a customs form and have specific restrictions. If you have buyers there, test such an address at checkout yourself.
When the carrier call fails
Live rates are computed for each cart, under a time limit. When they all fail and no other rate applies, Shopify shows backup rates. For US stores, Shopify-powered backup rates use USPS by default, with the most economical service available. Details, and why a flat rate is still worth having, in carrier-calculated shipping not showing.
Rates showing but not at the price you expect? Commercial vs retail rates and label adjustments are covered in shipping rates wrong at checkout.
A quick checklist
- Default package: a custom box, not a USPS flat rate box or envelope.
- Services ticked on the USPS option: Ground Advantage included, nothing retired.
- Variant weights filled in, in the right unit; carts within the service's limits.
- Stock at a physical US location that fulfils online orders.
- The USPS option exists in the profile of each product, in the buyer's zone.
- Own account: plan, connection, Calculate rates.
What our store check covers, honestly
The free store check builds a cart with one unit of one product, as an anonymous buyer, with one address per country — New York for the United States. When the US has no fixed rate, it also asks for live carrier rates, the way checkout does, and lists the USPS services that come back with their prices. So you see whether a one-item cart gets Ground Advantage, Priority Mail, both, or nothing.
It does not test heavy or mixed carts, other states, APO addresses, discount codes or logged-in buyers. When a country already has a flat or tiered rate, we do not ask for carrier rates there. Shopify limits how often a store's carrier rates can be read, so the result may be a reading from the last few hours, with its age shown; if USPS does not answer within 8 seconds, we report Could not confirm. Monitoring emails you when a known option, such as Ground Advantage, disappears.
Related
Sources: Shopify Help Center, “Troubleshooting and testing shipping rates”, “Setting up packages”, “Setting up shipping zones and rates”, “Activating calculated shipping with USPS”, “Third-party shipping carrier accounts and availability”, “Shipping with USPS” and “Backup shipping rates”, checked 17 October 2026. USPS, “Introducing USPS Ground Advantage” (10 July 2023) and the Ground Advantage and Priority Mail product pages, checked 17 October 2026. Merchant reports from the Shopify Community.