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What is flat-rate shipping?

What is flat-rate shipping? As the name suggests, it entails delivering all qualifying packages for a single, flat rate, regardless of weight. 

Rates and qualifications vary by shipping provider, but consumers and businesses appreciate the convenience offered by straightforward pricing structures. Here’s how it works.

How does flat-rate shipping work?

Flat-rate shipping means customers are charged a single price for their shipments. By extension, this means that the shipping cost isn’t influenced by factors such as the size of the package or its shipping weight.

Exact terms vary among shipping providers. For instance, the U.S. Postal Service (USPS) offers a variety of boxes to choose from. As long as your package can fit into one of them, you’ll just be charged a single fee.  

Other providers’ shipping services, such as FedEx’s “One Rate,” charge a single rate for packages that fall below a certain weight limit.

Who is flat-rate shipping best for?

What is flat-rate shipping used for? This shipping option can be used for just about anything as long as you meet the terms set by the shipping provider. It’s a great choice for:

  • Consumers looking for a simplified shipping process
  • Small business owners who need a predictable shipping cost
  • Those looking to ship heavier items without paying an additional cost

For example, some online retailers can use this service for e-commerce shipping, ensuring that all products are shipped at a single, predictable cost.

5 facts you should know about flat-rate shipping

Flat-rate shipping is among the most straightforward shipping methods, but you’ll need to know a few key things about the process.

1. USPS offers a variety of flat-rate package options

USPS offers several different types of flat-rate shipping options. Most of these options are organized around boxes that range in size from a small envelope to a large box six inches deep and over 12 inches on each side. For an additional cost, users can use an envelope for faster, express mail.

2. Anything that fits in the USPS flat-rate box can ship

USPS flat-rate shipping is extremely straightforward. You pay for the box, and anything that you can fit inside the box will ship for the same rate. And with several boxes to choose from, consumers have flexible options.

3. The cost of shipping flat rate is not affected by the weight of the package

Since shipping costs are based on the size of the box, the shipping weight doesn’t generally matter. However, the USPS does set an absolute weight limit of 70 pounds for all flat-rate packages.

4. Distance affects shipping costs

This is where it can get a bit more confusing for USPS customers. USPS flat-rate shipping is contingent on distance. USPS has nine shipping zones, with divisions based on distance. The further you ship, the more it costs, though again, these costs won’t vary based on package size or weight.

5. Packages are delivered between one and three days

USPS offers a delivery time of one to three days, with Sundays excluded. Customers who opt for express mail can get their items even faster. However, the cost will be higher.


What is flat-rate shipping best for? The advantages include:

  • Lower costs, especially when sending multiple packages over time
  • Predictable fees for e-commerce businesses
  • Reliable delivery times
  • The ability to ship heavy items without paying extra costs

The entire process is much simpler than paying based on package weight, which takes the guesswork out of mailing items across the country.


Despite these advantages, you still face drawbacks, including:

  • Cannot ship large or heavy items (70 pounds or more)
  • Pricing depends on USPS zones
  • Some packages may ship more cheaply using another mail class
  • No custom branding for e-commerce businesses
  • Some items may be the wrong shape to fit into a USPS box

USPS offers other shipping options to accommodate those who prefer to use an alternative shipping method.

Flat-rate shipping vs. standard shipping

How does flat-rate shipping compare to standard shipping? In many ways, the factors depend on the type and size of your package. But in general, customers can expect to see two main differences.

The first is cost. Flat-rate shipping will often be cheaper than standard shipping since you won’t have to worry about shipping weight.

However, this isn’t always the case. Some merchants may find it cheaper to use standard shipping for smaller items. Others may rely on the flat-rate option to avoid spending time running calculations.

The second difference is speed. Flat-rate shipping doesn’t always provide the fastest shipping speed, which can lead to customer dissatisfaction if you’re an ecommerce business owner. But with one- to three-day shipping options, it can still be a reliable delivery method.

A reliable option among many

Flat-rate shipping is ideal when sending small, heavy items, though that doesn’t mean it’s always the most cost-effective. At the same time, flat-rate options offer a convenient way for e-commerce merchants to fulfill orders without the added time of performing a series of business calculations.

In the end, flat-rate shipments provide a predictable, reliable shipping option, but it’s only one option among many.


Do customers prefer flat-rate shipping?

Customers prefer price transparency when it comes to shipping costs. They especially prefer companies that charge a single flat rate for all online orders, which can lead to more orders and less cart abandonment.

Why do companies use flat-rate shipping?

Many companies prefer flat-rate shipping because the costs are predictable. When you pay one flat rate for each package, it’s easier to integrate into your monthly budget.

Is flat-rate shipping trackable?

Yes. USPS flat-rate boxes come with a tracking number, allowing you and your customers to stay up-to-date regarding delivery.

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uShip helps you find and book with the right feedback-rated transporter who can haul your large items at the right price. Our technology makes rates and tracking transparent from pickup to delivery.

Ship The Way You've Always Wanted

uShip helps you find and book with the right feedback-rated transporter who can haul your large items at the right price. Our technology makes rates and tracking transparent from pickup to delivery.