A Complete Guide to Flat Rate Shipping

Posted on: October 11, 2021

    Your company’s profit margin is its lifeline. It doesn’t matter how good your products are if your profit margin doesn’t help you grow your business. So if you don’t ship your products in the most affordable and efficient way, you’re not only leaving money on the table, you’re also harming your company’s growth potential.

    Flat rate shipping is a shipping service that helps thousands of businesses lower their costs and become more profitable.

    By the end of this article, you’ll gain a better understanding of what flat rate shipping is, what it implies, and if it’s a good option for your online business. Read on to find out more.

    What Is Flat Rate Shipping?

    payment terminal and boxes on wooden pallet

    Flat rate shipping is a shipping service provided by large carriers that enables you to ship packages weighing less than 70 pounds for a single, flat rate.

    This service is attractive to many online businesses because it eliminates the need to weigh every package before sending it to your customer.

    In addition, since you know exactly how much you’re going to pay for shipping, you can easily price your products accordingly, making sure that your profit margins are healthy.

    How Does Flat Rate Shipping Work?

    Flat rate shipping makes it very easy to understand how much it would cost to send a package. Regular shipping fees are calculated based on the distance packages have to travel and their dimensional weight.

    On the other hand, when you use a flat rate shipping service, you pay a single, unchanging fee for every package, as long as it weighs less than 70 pounds.

    There are three steps involved in sending a package using a flat rate shipping service

    1. Packing - you pack your products in standard boxes (usually provided by the courier company)
    2. Fill in the details - you write the customer’s details and address on the package
    3. Shipping - you notify the carrier that you’re ready for pickup or you take your box to their office

    Flat Rate Shipping Restrictions

    Even though it can be very useful, flat rate shipping has some restrictions. For example, you can’t use it to send products that are too heavy or that don’t fit into the carrier’s standard boxes.

    However, if most of the products you offer fit into one of the boxes offered by the carriers, this shipping service can be very helpful.

    How Fast is Flat Rate Shipping?

    Flat rate shipments usually reach their destination within 1-3 days, depending on their destination.

    Flat Rate Boxes Explained

    Display of assorted FedEx packages and boxes

    Flat rate boxes come in three sizes-small, medium, and large - to meet your needs. However, it’s worth noting that large flat rate boxes are not available at all Canada Post locations, so you might want to check with your local post office before trying this service out.  

    The boxes provided by Canada Post are made out of at least 60% recycled materials and are 100% recyclable.

    You can purchase sets of 12 boxes at a time and use them when necessary.

    Flat Rate Box Weight Requirements

    All the flat rate boxes available have the same weight limit - 5 kg or 11 lbs.

    Flat Rate Box Size Requirements

    • Small box - 35cm x 26 cm x 5cm (10 3/8 in x 14 in x 2 1/8 in)
    • Medium box - 39 cm x 26 cm x 12 cm (15 3/8 in x 10 1/4 in x 4 3/4 in)
    • Large box - 40 cm x 30 cm x 19 cm (15 3/4 in x 11 13/16 in x 7 1/2 in)

    Flat Rate Box Shape Requirements

    All boxes are rectangular in shape. But even though all flat rate shipping boxes can hold a maximum of 5 kg, their shapes differ.

    Small boxes are slimmer, medium boxes offer more volume and large boxes allow you to pack bulky but lightweight products.

    How Much Does Flat Rate Shipping Cost in Canada?

    The cost of flat rate shipping in Canada depends on the carrier you use and the size of the package. Here are some tables that can help you estimate the costs:

    How Much is Canada Post Flat Rate Shipping?

    Canada Post

    Dimensions (L x W x H)

    Max weight


    Drop off location

    Small 35cm x 26 cm x 5cm

    (10 3/8 in x 14 in x 2 1/8 in)

    5 kg


    Street letter box or

    post office

    Medium 39 cm x 26 cm x 12 cm

    (15 3/8 in x 10 1/4 in x 4 3/4 in)

    5 kg


    Post office

    Large 40 cm x 30 cm x 19 cm

    (15 3/4 in x 11 13/16 in x 7 1/2 in)

    5 kg


    Post office

    How Much is USPS Flat Rate Shipping?

    The USPS offers a flat rate shipping service for businesses that want to ship packages across the border from the US to Canada.

    Here is an example of how much that would cost

    USPS flat rate shipping fees from US to Canada


    Max weight

    Price (USD)

    Flat Rate Envelope

    4 lbs


    Small Flat Rate Priced Boxes

    4 lbs


    Medium Flat Rate Boxes

    20 lbs


    Large Flat Rate Boxes

    20 lbs


    USPS Flat Rate Options

    USPS’s flat rate shipping service enables you to send packages of up to 20 lbs. from the US to Canada. It takes a package up to 10 days to reach its destination, depending on its destination.  

    How Much is FedEx Flat Rate Shipping?

    FedEx offers a flat rate shipping service for businesses that want to send packages from Canada to the US.

    FedEx flat rate shipping fees from Canada to the US


    Max weight

    Price (USD)

    Small Box

    25 kg


    Large Box

    44 kg


    FedEx Flat Rate Options

    FedEx’s flat rate shipping service combines the advantages of flat-rate pricing with its international priority services, allowing you to easily send large shipments across the border.

    The service is available from Monday to Saturday and your packages reach their destination within 1 - 3 business days.

    Best Flat Rate Shipping Companies

    Canada Post logo

    Canada Post Flat Rate Shipping

    Canada Post’s flat rate shipping is the best service currently available for Canadian businesses because it enables them to ship to all provinces and territories.

    The service is fast and inexpensive, so it can help you lower your shipping costs and provide a good post-shopping experience for your customers.

    usps logo

    USPS Flat Rate Shipping

    USPS flat rate shipping is a great option for businesses that want to ship packages across the border from the US to Canada.

    This service is fast, reliable and it enables you to send packages to Canadian customers without too much hassle.

    fedex logo

    FedEx Flat Rate Shipping

    FedEx flat rate shipping is a good option for Canadian businesses that want to ship large packages from Canada to the US.

    Even though it’s more expensive, this service’s weight capacity surpasses those of any other services available in Canada at the moment.

    Flat Rate Shipping Within Canada

    Canada Post’s flat rate shipping is the most popular shipping service in Canada. This service helps businesses deliver their products in a timely manner without going through the hassle of sourcing the packaging or weighing the packages before delivery.

    You can also use flat rate shipping services if you want to ship across the border to the United States.

    Advantages of Flat Rate Shipping for E-Commerce

    female small business owner using mobile app

    Flat rate shipping can substantially lower your shipping costs. In addition, they offer the major advantage of having a predictable cost, so you always know how much you would spend to ship a package.

    This gives you the ability to price your products correctly, so you always have a healthy profit margin after every transaction. Here are some other notable advantages.

    Total Flat Rate Package Weight up to 30 Kg

    If your online business doesn’t offer products weighing more than 30 kg, flat rate shipping can help you lower your shipping costs.

    The fact that you don’t have to supply the boxes yourself can also help you manage your shipments more efficiently.

    Flat Rate Boxes are Insured

    Flat rate boxes are insured, so you can rest assured that your product will either reach your customer or that you will be reimbursed for your product in case the carrier damages or loses it in transit.

    Flat Rate Shipping Has Parcel Tracking Included

    All flat-rate services include parcel tracking, so you can check their status with ease.

    Flat Rate Boxes are Easy to Drop Off

    Flat rate boxes are easy to manage. Once packed, you can drop them off at the courier or post office.

    How to Add Flat Rate Shipping to an Online Shop using a 3PL Company

    goods travel by conveyor belt at a warehouse fulfillment
    Goods travel by conveyor belt at a warehouse fulfillment center

    Ship Expert is a third-party logistics (3PL) provider that can help you integrate multiple carriers and fulfillment centers.

    With Ship Expert, you can easily implement flat rate shipping as one of your default shipping options, which can help you reduce your shipping costs.

    3PL Platform and E-commerce Store Connection

    Ship Expert’s platform integrates seamlessly with your eCommerce platform (such as Shopify, WooCommerce, or others), so you can manage your entire shipping and fulfillment process with ease.

    Inventory Storage in a 3PL Fulfillment Center

    When you use Ship Expert, you can store your products in multiple fulfillment centers that are strategically located across Canada. This helps you deliver your products faster and it also lowers your shipping costs because it reduces distance and transit time.

    Automatic Order Fulfilled by a 3PL Company

    Once you integrate Ship Expert into your eCommerce platform, all the orders processed by your online store can be automatically forwarded to the best fulfillment center. The products are picked, packed, and ultimately shipped by Ship Expert’s team to your customers.

    Send Tracking Info to Your Customers

    Your customers receive instant notifications once their products have been shipped, so they can follow the packages with ease.

    Flat Rate Shipping Alternatives

    Dynamic Checkout Shipping

    When you work with Ship Expert, you also have the option to use a dynamic checkout feature. The dynamic checkout feature automatically calculates the shipping costs based on your customers’ shipping addresses while they’re on the checkout page.

    While this checkout feature ensures that you never lose money on shipping, it can lead to a higher cart abandonment rate once your prospects see how much shipping would cost.

    Average Shipping Rates

    You can also lower your shipping costs by charging your customers a flat delivery fee based on your average shipping costs.

    To do this, you simply calculate your average shipping costs over the previous month, semester, year, etc, and use that as a reference.

    However, this method can lower your customer retention rates, especially for customers who are browsing small and inexpensive items.

    Expedited Shipping

    Expedited shipping is a great option because it promises that your customers will receive their products in a timely manner.

    Unfortunately, expedited shipping costs tend to be more expensive than regular shipping, which can act as a deterrent for some of your customers.


    Flat rate shipping is a great option for small businesses that want to keep their shipping costs under control. It can help you deliver your products in a timely manner and at a regular, small price, which can help you increase your profit margin and grow your business.

    Even though flat rate shipping is not overly popular in Canada, this trend is most likely to change in the near future.

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