FedEx One Rate vs Priority Mail Flat Rate (2026)

FedEx One Rate and USPS Priority Mail Flat Rate both let you ship a heavy item for a price set by the box rather than the scale, but they are built on different services. One Rate is a flat price per package type for FedEx Express services up to 50 pounds: one nationwide price on 2Day and Express Saver, distance bands on 2Day A.M. and the overnight services. Priority Mail Flat Rate is a single nationwide price for USPS's 2 to 3 day product up to 70 pounds.

If you need a guaranteed express delivery, One Rate is the flat rate that fits. If you need the heaviest, farthest parcel at one predictable price, Priority Mail Flat Rate usually is.

FedEx prices below are FedEx's published One Rate list prices effective April 20, 2026. Source: the FedEx One Rate pricing PDF. Every box on every service and zone band is in FedEx One Rate prices 2026.

How does FedEx One Rate work?

FedEx One Rate is a pricing option layered on top of FedEx Express services. According to FedEx:

• Services. One Rate applies to FedEx First Overnight, Priority Overnight, Standard Overnight, 2Day A.M., 2Day and Express Saver. It does not apply to FedEx Ground or Home Delivery, which have no flat rate.
• Packaging. You must use FedEx branded packaging: the FedEx Envelope, Extra Small Box (available since February 2, 2026), Pak, Small Box, Medium Box, Large Box, Extra Large Box or Tube. Sizes and free ordering are in FedEx flat rate boxes.
• Weight cap. Up to 50 pounds per package, with the Envelope capped at 10 pounds.
• Pricing. Flat by packaging type and service. FedEx 2Day and Express Saver are one nationwide price for each package type. Only 2Day A.M., Standard Overnight, Priority Overnight and First Overnight use three bands: Local (zone 2), Regional (zones 3 to 4) and National (zones 5 to 8, plus Alaska and Hawaii).
• Surcharges. Fuel, residential and delivery area surcharges are included in the One Rate price, while Saturday delivery, signature options, declared value above $100, on-call pickup and address correction are billed extra.
• Re-rating. An Envelope more than 3 inches or a Pak more than 5 inches on its shortest side is billed as a One Rate box by cubic volume, and a package over 50 pounds leaves One Rate.
• Alaska and Hawaii. These price at the National band. Express Saver is not available there, and One Rate does not cover shipments within Hawaii.
• Discounts. No account discounts apply to the One Rate prices.
• Coverage. FedEx includes up to $100 of declared value; more can be purchased.
• Guarantee. Express services carry the FedEx money back guarantee on delivery time, subject to FedEx terms.

The practical effect is that a dense 40 pound load in a FedEx Extra Large Box ships express at a known price with no dimensional weight surprise, because the box is the price.

How does Priority Mail Flat Rate work?

USPS Priority Mail Flat Rate is a pricing option on Priority Mail:

• Service. Priority Mail, quoted at 2 to 3 days, not guaranteed.
• Packaging. USPS supplied Flat Rate Envelope, Padded Flat Rate Envelope, Legal Flat Rate Envelope, Small Flat Rate Box, Medium Flat Rate Box (two shapes) and Large Flat Rate Box. The packaging is free from USPS.
• Weight cap. Up to 70 pounds in any flat rate container.
• Pricing. One price per container nationwide. Zone does not matter.
• Coverage. USPS includes up to $100 of insurance against loss or damage.

The Medium Flat Rate Box measures 11 1/4 x 8 3/4 x 6 inches (or 14 x 12 x 3 1/2 in the alternate shape), and the Large Flat Rate Box measures 12 1/4 x 12 x 6 inches outside, per USPS. If it fits and closes with the flaps flat, it ships.

Where do the two diverge?

Speed and guarantee. One Rate is express with a money back guarantee. Flat Rate is a 2 to 3 day estimate with no guarantee. If the arrival date is contractual, that alone decides it.

Weight. Flat Rate carries up to 70 pounds; One Rate stops at 50. A 60 pound box of books has one flat rate option, and it is USPS.

Distance. Priority Mail Flat Rate is one price nationwide, and so is FedEx One Rate on 2Day and Express Saver. Only 2Day A.M. and the three overnight services step up across Local, Regional and National bands, so a coast to coast overnight shipment costs more than a cross town one in the same box. Each overnight band is priced in FedEx One Rate overnight prices.

Packaging. Both require carrier branded containers, and both supply them. The FedEx Extra Large Box and Tube have no USPS flat rate equivalent, so a long or very large item may only have a One Rate option, or none at all.

Delivery footprint. USPS reaches PO Boxes and APO addresses. FedEx Express does not deliver to PO Boxes.

Weekend delivery. USPS Priority Mail delivers on Saturday at no extra charge in most locations. FedEx Express Saturday delivery is an option with its own terms.

Price. Here are the published prices side by side. FedEx 2Day (second day by 5 p.m.) and Express Saver (third day by 5 p.m.) cost the same in any US zone. Express Saver does not serve Alaska or Hawaii. The USPS column shows the retail (Post Office) price listed on usps.com on October 23, 2026; usps.com also lists lower commercial prices.

Package type	FedEx One Rate, 2Day or Express Saver (any US zone; no Express Saver to AK/HI)	Matching USPS Priority Mail Flat Rate container	USPS retail price
Envelope	$12.75	Flat Rate Envelope	$13.90
Extra Small Box	$13.40	No equivalent	n/a
Pak	$16.30	Padded Flat Rate Envelope	$15.00
Small Box	$19.55	Small Flat Rate Box	$14.65
Medium Box	$24.35	Medium Flat Rate Box	$25.80
Large Box	$32.05	Large Flat Rate Box	$36.10
Extra Large Box	$42.75	No equivalent	n/a
Tube	$42.75	No equivalent	n/a

The containers are matched by name, not by size, so compare dimensions as well as prices. These are carrier list prices, not what you would pay through any shipping software.

A worked example

You ship a 30 pound box of cast iron cookware from Ohio to California. The set fits in a USPS Large Flat Rate Box and also in a FedEx Extra Large Box (the 15 3/4 x 14 1/8 x 6 shape).

1. Check the weight caps. 30 pounds is under both the 50 pound One Rate cap and the 70 pound Flat Rate cap.
2. Check dimensional weight. Neither flat rate option uses it, which is the whole point for a heavy dense box. On a regular weight based FedEx Ground or UPS Ground label, the 12 1/4 x 12 x 6 box would be 882 cubic inches, which divides by 139 to about 6.3 pounds, so it would rate at the actual 30 pounds anyway.
3. Check the distance band. On FedEx 2Day or Express Saver the One Rate price is the same in every zone. On the overnight services and 2Day A.M., Ohio to California is National, the most expensive band. For USPS Flat Rate the zone is irrelevant.
4. Check the promise. If the customer bought standard shipping, the Priority Mail Large Flat Rate Box is the candidate to compare against weight based ground rates. If the customer needs it in two days with a guarantee, FedEx 2Day One Rate in the Extra Large Box is the candidate.
5. Compare. Quote the flat rate options next to weight based USPS, UPS and FedEx rates and pick the lowest that meets the deadline.

The point of the example is that the two flat rate programs rarely compete head to head. One answers "express, predictable, under 50 pounds." The other answers "heavy, far, no rush, under 70 pounds." Weight based ground rates are the real competitor to both, which is why comparing everything on one screen matters. Our flat rate vs weight based shipping page covers when the flat price loses to a weight based one.

What about UPS Simple Rate?

UPS Simple Rate is a flat rate by box size on UPS Ground and UPS air services, in your own box up to 1,728 cubic inches. It is the closest UPS answer to a "ground flat rate" search, because FedEx One Rate is express only and has no ground version. We do not quote UPS prices here, so check ups.com for current Simple Rate prices.

How should you decide per order?

1. Guaranteed delivery date required: FedEx One Rate in the smallest FedEx box that fits, or another express service.
2. Over 50 pounds: Priority Mail Flat Rate is the only one of the two flat rate programs that takes it; compare it with UPS or FedEx Ground.
3. Heavy, dense, going far, no deadline: Priority Mail Flat Rate is the first thing to check.
4. Light or going a short distance: neither flat rate program is likely to win; a weight based rate usually does.
5. Item value over $100: add declared value or insurance on either carrier.

GoatLabels quotes USPS, UPS and FedEx on domestic parcels (DHL on international lanes), including the USPS flat rate prices you qualify for, with no monthly fee on Free (up to 50 shipments a month), and labels are paid from a prepaid wallet, as described on the pricing page. Orders from Shopify, Amazon, eBay, Etsy, Walmart and nine other connected stores land in one "To Ship" queue, and the AI assistant can draft the label from an order screenshot if you are not on a connector yet. Sign up to run your heaviest product through both programs, and check the FAQ for how flat rate packaging is selected in the app.

FAQ

Is FedEx One Rate cheaper than Priority Mail Flat Rate?

It depends on the container. At FedEx's published 2Day and Express Saver prices and the USPS retail prices checked October 23, 2026, FedEx is lower for the Envelope, Medium Box and Large Box matches and USPS is lower for the Pak and Small Box matches.

Which has the higher weight limit, FedEx One Rate or Priority Mail Flat Rate?

Priority Mail Flat Rate, which allows up to 70 lb in any container. FedEx One Rate caps envelopes at 10 lb and paks, boxes and tubes at 50 lb.

Is the delivery date guaranteed on FedEx One Rate or Priority Mail Flat Rate?

FedEx One Rate rides Express services that carry the FedEx money back guarantee on delivery time, subject to FedEx terms. Priority Mail Flat Rate is a 2 to 3 day estimate with no guarantee.

Do FedEx One Rate and Priority Mail Flat Rate deliver to PO Boxes?

Priority Mail Flat Rate does, and USPS also reaches APO addresses. FedEx Express does not deliver to PO Boxes, so One Rate cannot either.

Does UPS have a flat rate like FedEx One Rate and Priority Mail Flat Rate?

UPS Simple Rate is the closest, a flat rate by box size on UPS Ground and UPS air services, in your own box up to 1,728 cubic inches. Check ups.com for current Simple Rate prices.

What happens if I overstuff a FedEx One Rate envelope or pak?

An envelope more than 3 inches or a pak more than 5 inches on its shortest side is re-rated as a One Rate box by cubic volume. A package over 50 lb leaves One Rate.

Does FedEx One Rate ship to Alaska and Hawaii?

Yes, at National-zone prices. Express Saver is not available there, 2Day A.M. and Standard Overnight serve Hawaii outbound only, and shipments within Hawaii are excluded.