7 Reasons to Consider USPS Flat Rate Shipping

The UPS rate is the daily rate for businesses with scheduled pick-ups. The USPS rates are for the commercial base tier. The UPS rates do not include dimensional weight and do not include the 30-cent peak surcharge per package that was in effect at the time of writing.
For further comparison, here are a few helpful links.
Here are seven reasons to consider USPS’s flat-rate and prepaid flat-rate boxes and envelopes.
To compare USPS to FedEx yourself, try these links.
Let’s now compare charges for USPS flat-rate boxes to FedEx Home Delivery and FedEx One Rate.

Advantages of Flat Rate Shipping

For more than 20 years, the United States Postal Service has offered flat-rate boxes and envelopes that have helped online stores reduce shipping costs while improving shoppers’ buying experience.
Shipping can be a significant challenge for ecommerce merchants. A business must pay shipping and carrier fees, buy packing materials, and hire labor to pick and pack each order.

  • Free boxes. USPS flat-rate boxes are free. Merchants order them at no cost and start shipping. Merchants will still need to purchase packing peanuts or similar cushioning material, but avoiding as much as $1 per box can be huge savings. (Other carriers, I should add, also include free boxes with their flat-rate services.)
  • Known costs. Although shipping calculators are accurate, there are times when the actual shipping cost for a package exceeds what the merchant expected. Flat-rate boxes have a known cost — no surprises.
  • Priority delivery. The USPS flat-rate boxes are Priority Mail, meaning a package usually arrives in two or three days. Priority Mail packages also receive special handling and extra care in the USPS system.
  • No surcharges. The USPS does not add fuel, residential, or Saturday delivery surcharges to any shipment —  significant in an era of high fuel costs.
  • More addresses. The USPS delivers to every U.S. address, including post office boxes and government addresses such as APO (Army/Air Force Post Office), FPO (Fleet Post Office, for Navy), and DPO (Diplomatic Post Office, for U.S. embassies). Other U.S. carriers can only reach these addresses when the postal service delivers the last mile.
  • Security. Only the USPS is authorized to place packages in mailboxes. Plus, unlike some carriers that leave items on the porch, the USPS will try to re-deliver large packages in some cases. Not abandoning packages may help prevent purchase fraud and theft.
  • Law enforcement protection. Flat-rate USPS shipments are protected by U.S. law enforcement, which, again, contributes to less fraud and theft.

USPS Flat Rate Prices

Moreover, free and fast ecommerce delivery is ubiquitous. Most online stores now offer free shipping — thank Amazon, L.L. Bean, and other free shipping pioneers. Shoppers expect to place an order, obtain free shipping, and receive that order in about two days.
Fortunately for merchants, the USPS is a leader in flat-rate shipping services. The postal service’s flat-rate offering began in February 1991 when it introduced the Priority Mail flat-rate envelope.

Flat Rate ServiceDimensionsAt the Post OfficeCommercial Base
Flat Rate Envelope12 1/2″ x 9 1/2″$8.95$7.75
Padded Flat Rate Envelope12 1/2″ x 9 1/2″$9.65$8.45
Legal Flat Rate Envelope15″ x 9 1/2″$9.25$8.05
Small Flat Rate Box8 11/16″ x 5 7/16″ x 1 3/4″$9.45$8.25
Top-loading Medium Flat Rate Box11 1/4″ x 8 3/4″ x 6″$16.10$14.25
Side-loading Medium Flat Rate Box14″ x 12″ x 3 1/2″$16.10$14.25
Large Flat Rate Box12 1/4″ x 12 1/4″ x 6″$21.50$19.20
APO/FPO/DPO Flat Rate Box12 1/4″ x 12 1/4″ x 6″$20.00$17.70
Large Flat Rate Board Game Box24 1/16″ x 11 7/8″ x 3 1/8″$21.50$19.20

USPS Rates vs. UPS

In a hyper-competitive market where consumers expect free shipping regardless of order size, USPS flat-rate boxes can help merchants preserve margins. And the boxes typically ship faster than ground service, potentially improving the shopper’s experience.
The USPS offers several flat-rate shipping options, including various envelopes and boxes. Each flat-rate envelope or box has at least two pricing tiers. The “at the post office” rate is what a very low-volume shipper would pay. But nearly any ecommerce business could obtain the “commercial base” rate.
Now let’s look at large box equivalents. Here the packages are 10 and 15 pounds. In this example, UPS Ground is more competitive when the packages are less dense — i.e., lighter relative to box size.
Let’s compare the rates for USPS flat-rate to UPS Ground for small and large boxes and UPS Simple Rate, which is a flat-rate service.

Small Box | UPS ZoneUSPS RateUSPS Days to DeliverUPS Ground Rate 1 lb.UPS Ground Rate 5 lb.UPS Ground Days to Deliver
Zone 8$8.252 to 3 Days$11.84$17.135 Days
Zone 7$8.252 to 3 Days$11.64$16.154 Days
Zone 6$8.252 to 3 Days$11.51$15.343 Days
Zone 5$8.252 to 3 Days$11.13$14.732 Days
Zone 4$8.252 to 3 Days$10.65$13.702 Days
Zone 3$8.252 to 3 Days$9.77$12.492 Days
Zone 2$8.252 to 3 Days$9.36$11.241 Day

Finally, let’s consider FedEx’s flat-rate offering, One Rate. Although it’s called “One Rate,” each box size has three rates, all based on distance. Zone 2 is any shipment within 150 miles. Zones 3-4 are between 151 and 600 miles. Zones 5-8 represent distances of 601 miles or more. All of the rates are for FedEx Express Saver — delivered in three days or fewer. Note that FedEx One Rate boxes are a little larger than their USPS counterparts.

Large Box | UPS ZoneUSPS RateUSPS Days to DeliverUPS Ground Rate 10 lb.UPS Ground Rate 15 lb.UPS Ground Days to Deliver
Zone 8$19.202 to 3 Days$20.84$27.425 Days
Zone 7$19.202 to 3 Days$18.86$24.764 Days
Zone 6$19.202 to 3 Days$16.80$20.563 Days
Zone 5$19.202 to 3 Days$16.23$17.932 Days
Zone 4$19.202 to 3 Days$14.91$15.842 Days
Zone 3$19.202 to 3 Days$13.62$15.172 Days
Zone 2$19.202 to 3 Days$12.69$14.051 Day

With the USPS flat-rate boxes, “if it fits, it ships” (up to 70 pounds), making the service especially good for dense, heavy products relatively small in size.

USPS Box EquivalentUSPS RateUPS Ground Simple RateUPS 3-day Select Simple Rate
Small Box$8.25$9.45$16.10
Large Box$19.20$19.60$37.10

Next is a comparison of rates for USPS large flat-rate boxes and their equivalents.

USPS Rates vs. FedEx

The USPS offers some of the most attractive options among the various carriers available to North America-based online merchants.
More than a decade later, on November 20, 2004, the USPS released the Priority Mail flat-rate box. Today, USPS flat rate services address many ecommerce delivery problems and costs. Even enterprise retailers such as Amazon and Walmart use the service.

Small Box | UPS ZoneUSPS RateUSPS Days to DeliverFedEx Home Delivery Rate 1 lb.FedEx Ground Rate 5 lb.FedEx Home Delivery Days to Deliver
Zone 8$8.252 to 3 Days$11.84$17.135 Days
Zone 7$8.252 to 3 Days$11.64$16.154 Days
Zone 6$8.252 to 3 Days$11.51$15.343 Days
Zone 5$8.252 to 3 Days$11.13$14.732 Days
Zone 4$8.252 to 3 Days$10.65$13.702 Days
Zone 3$8.252 to 3 Days$9.77$12.492 Days
Zone 2$8.252 to 3 Days$9.36$11.241 Day

This first comparison considers shipping rates for 1- and 5-pound packages that fit in the 8 11/16 inch by 5 7/16 inch by 1 3/4 inch small flat-rate box versus a similar-sized package shipped via UPS Ground.

Large Box | UPS ZoneUSPS RateUSPS Days to DeliverFedEx Home Delivery Rate 10 lb.FedEx Ground Rate 15 lb.FedEx Home Delivery Days to Deliver
Zone 8$19.202 to 3 Days$20.84$27.425 Days
Zone 7$19.202 to 3 Days$18.86$24.854 Days
Zone 6$19.202 to 3 Days$16.80$20.633 Days
Zone 5$19.202 to 3 Days$16.28$17.892 Days
Zone 4$19.202 to 3 Days$14.91$15.892 Days
Zone 3$19.202 to 3 Days$13.62$15.242 Days
Zone 2$19.202 to 3 Days$12.69$14.121 Day

The rates shown below were collected on June 20, 2022 from the USPS’s website and represent domestic U.S. prices.

USPS Box EquivalentUSPS RateFedEx Express Saver Zone 2FedEx Express Saver Zone 3-4FedEx Express Saver Zone 5-8
Small Box$8.25$12.05$13.80$15.30
Large Box$19.20$24.20$26.20$26.70

UPS’s Simple Rate service is available for a few service levels, including Ground and 3-day Select. These rates are for the contiguous United States. UPS Ground service can take up to five days to deliver. UPS 3-day Select can take one to three days.

Preserve Margins

This first set of rates is based on a USPS small flat-rate box or its equivalent compared to the FedEx Home Delivery service.