
Discover how flat rate shipping works and when to leverage it to save time and money and optimize your order fulfillment process
In eCommerce where delivering orders is the backbone of the industry, optimizing your eCommerce fulfillment and shipping strategies is integral to your business. Figuring out how to calculate delivery costs can be a hassle. Weight, dimension, and restrictions make it difficult to know how much to charge. But in some situations, flat rate shipping can save you time (and money) by offering a simple and predictable pricing model.
So what is flat rate shipping? Keep reading to learn the benefits, costs, and best practices of flat rate shipping for your eCommerce business.

What is flat rate shipping?
Flat rate shipping is a shipping type where the cost is determined by the package rather than the dimensions or weight. This shipping method has a limitation on the size and weight of the box, so any package that doesn’t exceed that limitation is charged a flat fee.
Many eCommerce businesses utilize flat rate shipping to simplify the process and easily calculate costs and delivery times. Almost all private couriers offer a flat rate shipping service, but they often have different limitations and prices.
For example, USPS offers a shipping service called Priority Mail Flat Rate. This service charges a fixed price on packages weighing up to 70 lbs with combined length and girth not greater than 108 inches.
Flat rate shipping vs standard shipping: Key differences
Flat rate shipping and standard shipping are both used by eCommerce businesses to deliver packages. Here’s a look at the key differences between both shipping types:
Cost
This one is pretty much self-explanatory. Flat rate shipping services charge a fixed fee for certain packages that meet the weight and size set by the courier. So for USPS Priority Mail Flat Rate, they take a fixed fee but don’t charge for additional services such as fuel surcharges and package pickup.
For comparison, let’s take a look at USPS’s standard shipping service: Ground Advantage. This service takes the package weight into account to determine the final price.
Delivery time
Flat rate shipping has a flat delivery time too! Due to the standardized process, it’s much easier to know what’s the expected delivery time for packages sent with flat rate shipping. USPS Priority Mail Flat Rate delivery packages across the US within 1 – 3 business days.
Standard shipping, however, can be faster or slower than flat rate shipping, depending on the package and the courier. USPS Ground Advantage, for instance, offers 2 – 5 business days for delivery.
Coverage area
Flat rate shipping services often have a specified coverage area. If the area is within California, for example, the shipping price won’t change whether the destination is San Diego in the south or Eureka in the north of the state. The same doesn’t apply to standard shipping, as the price can vary widely based on the destination.
Prohibited items
Due to the limitations of flat rate shipping packages, it often doesn’t support all types of items. For example, items classified by USPS as “hazardous materials” cannot be accepted for the Priority Mail Flat Rate service. If you need to ship these restricted items with USPS, you need to use standard shipping methods like Ground Advantage.
Benefits of flat rate shipping
Flat rate shipping offers a wide range of benefits for eCommerce brands, including:
Simplified process: Flat rate shipping is straightforward. If you have items that have similar weights and sizes, you won’t need to spend much time calculating shipping costs.
Cost-effectiveness: Large packages can be shipped at a lower rate and without additional charges.
Transparency: With a set cost and delivery time, customers know exactly what to expect, leading to a better shopping experience.
Predictability: With flat rate shipping, there won’t be any surprises in costs and delivery times, allowing you to better plan your eCommerce fulfillment strategy.
Disadvantages of flat rate shipping
Given the unique pricing model of this shipping method, it has drawbacks as well. Here are some of its disadvantages to keep in mind:
Might get expensive (sometimes): Flat rate shipping may not offer low rates for smaller packages or nearby delivery addresses.
High customer expectations: The fixed delivery time is a double-edged sword. If an order is delayed, even slightly, it may lead to dissatisfaction since customers expect their order to arrive as promised.
Limited coverage: Flat rate shipping may not cover as many locations as standard shipping.
Not all items are supported: Most flat rate shipping services have restrictions on the types of items that are accepted.
What couriers offer flat rate shipping?
Almost all couriers offer flat rate shipping services. However, each service has different features, limitations, and prices than the other.
Top flat rate shipping services in the US with their delivery time:
Courier | Shipping Service | Delivery Time (Business Days) |
USPS | USPS Priority Mail Flat Rate | 1 – 3 |
FedEx | FedEx One Rate | 1 – 3 |
UPS | UPS Simple Rate | 2 – 3 |
Should eCommerce sellers use flat rate shipping?
Flat rate shipping can be very helpful for enhancing your eCommerce fulfillment operations. But to utilize this shipping method to the fullest, you should be selling a lot of items that are similar in size and weight. In this case, you can save more time (and potentially money) by opting for a flat rate shipping service that fits your needs.
There are a few instances where you need to avoid flat rate shipping, however. If your customer base is spread across a very large area, the limitation of flat rate shipping would be challenging. In addition, if you have a wide variety of items that are not similar in dimension and weight, opting for flat rates may not be cost-effective or time-efficient.
Still not sure about your shipping strategy?
Perfecting shipping can feel like a never-ending challenge, but it doesn’t have to be. As an eCommerce brand, your focus should be on what you do best – growing your business and maximizing sales.
For shipping, it should be handled by professionals who know how to get things done. At Lansil Global, we’ve been helping eCommerce brands take their USA order fulfillment strategy to the next level. From our warehouses in Nevada and Pennsylvania, we ship to all states in 2 to 4 days. Our team is well-suited to advise you on which shipping method to use.
Let’s discuss how we can help you move forward with eCommerce shipping. Get in touch with us today.