Flat Rate Shipping Time


November 22, 2023

An estimated 2.5 million online retailers power the eCommerce business industry in the United States. Online businesses rely heavily on the services of shipping companies to provide the logistics needed to cater to the flood of orders and deliveries from customers. 

One way big companies like USPS (United States Postal Services), FedEx (Federal Express), and UPS (United Parcel Service) help online businesses is to provide flat-rate shipping. 

What is flat-rate shipping, and how long does it take for packages sent through this shipping option to reach their destination? 

This article explains flat-rate shipping and how it benefits customers, especially online businesses. It also tackles the delivery time for flat-rate shipping, especially those provided by USPS via Priority Mail. 

 Furthermore, this write-up tackles whether flat-rate shipping is better than other delivery options. 

If you need access to contact information for a local post office when you want to send packages using flat-rate shipping, visit FindPostOffice.org. You can access over 31,330 USPS retail offices, including military post offices, in various installations worldwide. 

How Long Is the Flat Rate Shipping Time?

The flat rate shipping time depends on the shipping method you’ve chosen. Usually, the delivery timeframe is from one to three days (excluding Sundays). It’s difficult to give an exact delivery time because many factors can extend the delivery time needed for shipments to reach their final destination. 

USPS Flat Rate Shipping Delivery Times

For USPS, flat-rate envelopes or packages typically use the Priority Mail shipping option. The delivery time is one to three business days. 

What Is Flat Rate Shipping?

Flat-rate shipping comes with a fixed price and usually makes use of standard packaging such as an envelope or a box. The price is not based on the item’s size, weight, and dimension. 

The flat-rate shipping options standardize shipping costs, removing the huge postage variations for parcels with varying weights, dimensions, or delivery locations. 

Do Couriers Offer Flat Rate Shipping?

Almost all carrier companies in the United States, like FedEx (Federal Express) and UPS (United Parcel Service), provide flat-rate shipping. Having a standard shipping rate is cost-effective and convenient, especially for eCommerce business owners with regular shipment schedules. 

Flat-Rate Shipping Services at USPS, FedEx, and UPS

The big three shipping giants in the United States have versions of flat-rate shipping services to cater mostly to eCommerce shipping needs. 

USPS Priority Mail Flat-Rate and Priority Mail Express Flat-Rate

The U.S. Postal Service offers Priority Mail Flat Rate and Priority Mail Express Flat Rate. Below is a guide for customers looking to use these services.

Weight, Size, and Shape Requirements

The following are dimension requirements for USPS flat rate packages shipped via Priority Mail. 

Use USPS Priority Mail Packaging and Pay a Flat Rate

  • Flat-rate prices remain the same for parcels weighing up to 70lbs and going anywhere in the United States. 
  • Priority Mail Flat Rate envelopes and boxes come in standard sizes, reducing the need to measure them constantly during shipping.
  • Flat-rate envelopes or shipping boxes must have container flats capable of closing within the package container’s normal folds.  

Use Your Own Box and Pay by Weight and Zone (Distance)

Note that if you use a flat-rate envelope or box, you take advantage of its standard price. 

However, if you use custom boxes, you’ll pay by weight and distance. The maximum weight limit, even for personalized packaging, is 70lbs. 

Furthermore, you must ensure the packaging meets the courier’s standards. For USPS, the combined dimensions of a package must not exceed 108in. 

FedEx One Rate

The FedEx One Rate is an express air service rate that doesn’t charge customers for fuel and residential delivery expenses. 

This one-rate service provides customers with predictable shipping charges, which they can use to effectively plan their delivery budget. The services where FedEx One Rate is applicable are the following:

UPS Simple Rate

UPS, one of FedEx’s competitors in shipping services worldwide, offers a similar flat-rate service called UPS Simple Rate. However, UPS provides five packaging rates and four shipping speeds for shipping parcels anywhere in the United States. 

UPS five packaging rates:

  1. Extra Small: Starts at $10.20
  2. Small: Starts at $13.35
  3. Medium: Starts at $16.05
  4. Large: Starts at $21.05
  5. Extra Large: Starts at $26.05

UPS four shipping speeds:

  1. Delivery Within Five Days
  2. Delivery Within Three Business Days
  3. Second Day Delivery
  4. Next-Day Delivery

How Does Flat-Rate Shipping Work?

Flat-rate shipping is a way to pay for package deliveries without weighing or measuring the parcel to determine its postage cost

Because of the flat rate, you can stuff any number of items into a standard flat-rate envelope or box as long as the parcel doesn’t exceed the weight limit. 

The following explains how flat-rate shipping works and how customers can get this service. 

Order Your Flat Rate Packaging

The first thing you need to do is get hold of flat-rate packaging (envelope or box). You can get this for free in most local post offices near you. Alternatively, you can order these packaging materials from the Postal Store and have them delivered to your home. 

Pack Your Order Into the Box

Once you’ve ordered your flat-rate envelope or box, you can pack it with items you want to ship. The convenience of flat-rate shipping can be fully realized by eCommerce stores that regularly ship bulk orders to customers. 

You don’t have to worry about varying prices per delivery. You only need to ensure the items you pack into the box or envelope don’t exceed the provided weight limit of 70lbs. Remember that in flat-rate shipping, the prices are based on the envelope or box sizes. 

Add the Address

After securing the envelope or box, you must provide the correct address to ensure your package’s fast and accurate delivery. The information should be 100% correct, or else it may cause delays in the shipping process. 

In most cases, the following information is required in your package address:

  • Recipient’s name
  • Organization’s name
  • Street address
  • Suite or apartment number
  • City, state, and ZIP (zone improvement plan) code

Buy Your Postage

After ensuring your address is accurate, you can buy postage by paying at your local post office or using an online service like USPS Click-N-Ship. This USPS service allows customers to create shipping labels and pay postage online. 

Ship Your Items

Once everything is accomplished, you can set your package up for delivery. You can drop your parcel at the local post office or have a USPS carrier pick it up from your home. 

USPS provides a free package pickup service, which anyone can take advantage of to reduce the time needed to visit the post office often. 

Flat Rate vs. Standard Shipping

Flat rates and standard shipping have benefits that can help customers in various ways. However, flat-rate shipping may be more efficient for businesses that regularly ship packages. One parameter differentiating flat-rate shipping from other shipping methods is delivery time. 

What Determines Shipping Speed?

The shipping speed is how fast a package is shipped from a USPS warehouse to its intended destination. If a customer uses Priority Mail Express to ship flat-rate packages, they may expect the parcel to be delivered to their intended destination the following business day. 

How Much Does Flat-Rate Shipping Cost?

The shipping rate of a flat-rate package depends on the current rate provided by courier services like USPS. Here are some of the flat rate options for USPS and their pricing: 

PackagingPost Office PricesCommercial Prices
Priority Mail Flat-Rate Envelope$9.65$8.05
Priority Mail Express Flat-Rate Envelope$28.75$24.90
Medium Flat-Rate Box (top-loading)$17.10$14.75
Medium Flat-Rate Box (side-loading)$17.10$14.75
Large Flat-Rate Box$22.80$19.90
  • Priority Mail Flat-Rate Envelope: Post office prices start at $9.65, while commercial base pricing begins at $8.05. 
  • Priority Mail Express Flat-Rate Envelope: Post office prices start at $28.75, while commercial prices start at $24.90.
  • Medium Flat-Rate Box (top-loading): Post office prices start at $17.10, while commercial prices start at $14.75. 
  • Medium Flat-Rate Box (side-loading): Post office prices start at $17.10, while commercial prices start at $14.75.
  • Large Flat-Rate Box: Post office prices start at $22.80, while commercial prices start at $19.90.

USPS Flat Rate Boxes and Envelopes

The USPS Flat-Rate service typically comes with box and envelope packaging. Customers can get these packages free of charge from a local post office. They can also purchase one from the Postal Store. 

Once you’ve purchased one from the Postal Store, you’ve already paid for the postage for that flat-rate box or envelope. USPS calls these items prepaid flat-rate envelopes or boxes. 

However, the items you pack into these package containers must not exceed the 70-pound weight limit. Also, the content should fit the container without any modifications, like altered folds.

Why Use USPS Flat Rate Shipping for eCommerce?

An eCommerce business can benefit most from flat-rate shipping because of the expedited process. Companies don’t need to measure and weigh each package. Every Priority Mail flat-rate box or envelope purchased from the Postal Store is prepaid. 

The only thing to worry about is whether the contents are correctly packed inside the envelope or box. Here are some benefits that make flat-rate shipping more appealing than other shipping methods. 

Package Anything Up to 70 Pounds

You can stuff your package with any order from your eCommerce store so long as it doesn’t exceed 70lbs. Additional weight may result in additional postage charges.

Automatically Insured Up to $100

When you ship flat-rate envelopes and boxes via Priority Mail, your items are automatically insured up to $100. This insurance can give shippers the peace of mind they need when shipping bulk orders. 

Drop Off at Any USPS Store

You can drop your flat-rate package at any USPS store or facility near you. Find the nearest post office in your area by visiting FindPostOffice.org. You can access over 31,330 USPS retail stores to process and ship your package. 

USPS Tracking Included

Priority Mail services include USPS tracking, the method used to monitor package deliveries. Customers get a tracking number once they’ve purchased postage or when the post office receives the package. 

If you get this tracking number, type it into the USPS tracking page’s search bar and get notifications on your delivery. 

USPS Priority Mail Restrictions

Priority Mail also has restrictions aside from exceeding the weight limit or modifying the flat-rate envelope or box to fit an unevenly shaped item. 

The additional restrictions focus mainly on the type of items sent. Examples of prohibited items are the following:

  • Explosives
  • Firearm ammunition
  • Airbags
  • Alcohol
  • Gasoline
  • Liquid Mercury
  • Marijuana (medical or not) 

Should You Use Flat Rate Shipping?

Flat-rate shipping is especially beneficial for online businesses with regular customers. Instead of worrying about varying shipping costs, shippers and retailers only need to know one price. 

Which Flat-Rate Shipping Service Is Right for You?

It’s best to consider the pros and cons of a shipping service to determine whether it’s right for you. Remember that USPS created different shipping methods to cater to customers with varying needs. 

A certain shipping service may be beneficial for a specific shipping need but may not be practical for another. 

The Pros and Cons of Flat-Rate Shipping

Here are the benefits and drawbacks of using flat-rate shipping. Customers can apply the information on this list to other shipping companies offering flat-rate services. 

The Pros

This list starts with the benefits of using flat-rate shipping methods. Remember that these are general benefits observed by USPS customers who have purchased this service. 

Predictable Shipping Costs

The flat-rate shipping is a consistent price service that isn’t affected by the weight and size of the item. Predictable shipping costs can help business owners calculate the budget for shipping expenses. 

Using Carrier-Supplied Packaging

You can get free USPS packaging from a post office or order prepaid flat-rate packaging from an online store. Businesses don’t need to allot a budget specifically for packaging as USPS readily provides packaging materials. 

New and small businesses can use carrier-supplied packaging, especially entrepreneurs who can’t produce custom packaging yet. 

Easy Free Shipping Promotions

Exact shipping costs can help business owners calculate shipping promotions to advertise their products and services. Flat-rate shipping prices don’t typically change abruptly, which makes pricing and costing easier for businesses. 


The single price rate for a flat-rate package simplifies the shipping process. Packaging and postage only take one payment that doesn’t rely on the weight and dimensions of the items shipped. 

Insurance and Tracking

Most carriers’ flat-rate shipping options include insurance and tracking services. For instance, USPS Priority Mail provides insurance and USPS tracking services for flat-rate envelopes and boxes shipped via this method. 


The delivery process speed is fast for flat-rate shipping because it eliminates many processes involved in standard shipping. One example is determining the shipping price by weighing and measuring the item. 

Furthermore, in the case of USPS, flat-rate shipping is done via Priority Mail, which is the company’s faster delivery method than other shipping options. 

The Cons

For a balanced view, here are some drawbacks or cons some customers experience when using flat-rate shipping. 

Merchants Can Spend More on Shipping Than They Need to

A business exclusively using flat-rate shipping methods may spend more on shipping if a customer orders an item way below the maximum weight limit. Using flat-rate shipping for inconsistent, short-haul deliveries with piecemeal orders is impractical. 

It Doesn’t Always Create the Best Customer Experience

Some customers may find the pricing for flat-rate shipping unreasonable, especially if the ordered package is cheaper than the shipping cost. 

Lost Branding Opportunities

Using flat-rate packages means customers will only see the courier’s brand once the package arrives, not yours. This lost branding opportunity may not concern other shippers but may be crucial for other eCommerce companies. 


The delivery speed, especially for Priority Mail, is fast. However, one can’t discount the problem caused by delays, which can happen anytime. Some shippers, including small business owners, experience delays in deliveries handled by USPS, which may affect customer experience. 


For eCommerce start-ups, using a flat-rate shipping service may be a hassle, especially if you don’t know your demographics yet. 

The constant shift in shipping options to cater to specific customer orders that do not suit flat-rate packages can be a hassle. 

If you prioritize using flat-rate shipping services, this can be a problem for customers purchasing small items and paying for oversized packaging. They may feel overcharged and dissatisfied. 

When Is It Cheaper to Do Flat Rate Shipping?

The most straightforward answer is when shipping orders are regular, and customers typically purchase more than one item. 

Businesses with centralized processing facilities or warehouses may also benefit from flat-rate shipping as they don’t need to pay for cross multiple shipping zones. 

A shipping zone is the shipping company’s way of categorizing the distance between the sender and recipient. The zone closest to the origin of the delivery is usually classified as zone 1. 

At the same time, more distant locations may reach up to zone 8. Shipping companies classify zones according to ZIP codes and not miles. 

When Is It Not Cheaper to Do Flat Rate Shipping?

It’s not cheap or practical to use flat-rate shipping when orders are not regular, and deliveries are short hauls. 

Using flat-rate packaging for items you can send via more inexpensive methods like First-Class Mail or First-Class Package is also impractical. 

First-Class Mail is the most affordable USPS service for shipping items that weigh 1oz to 13oz. So, if the customer ordered one item that can be sent via First-Class Mail, it’s more efficient than sticking to flat-rate shipping. 

How Does Flat-Rate Shipping Compare With Other Services?

For select orders, shipping options other than flat-rate shipping are cheaper. However, for eCommerce sites and other online businesses with regular deliveries, flat-rate shipping may be the advisable choice. 

Alternatives to Flat Rate Shipping

Shipping companies have more than one way to provide affordable delivery options for people, especially business owners, who need regular shipping services. 

  • USPS Priority Mail regional rate boxes: This service is a low-cost shipping option where the postage price is based on the destination.
  • Discounted delivery service: There are instances where shipping companies offer discounted rates for different shipping options due to various reasons. Shippers can take advantage of these discounts. 

Dynamic Checkout

Aside from the money-saving options flat-rate shipping provides, business owners can also improve customer experience. One option is to use dynamic checkout in the ordering process. 

A dynamic checkout allows customers to plan the day they want to receive their parcels. 

Business owners can integrate a dynamic checkout option into the checkout process of their store page to improve customer experience. This checkout option reduces customers’ steps just to order an item from your store. 

Average Shipping Costs

Getting the average cost for flat-rate shipping requires understanding the different shipping methods and rates of USPS and other shipping companies.

FedEx One Rate, the company’s flat-rate shipping option, starts at $11.10. On the other hand, UPS Simple Rate starts at $10.20 for extra small flat-rate packages. 

Additional Information

Here is some additional information that may be essential for customers using the flat-rate shipping service provided by USPS. 

Shipping to a Military Post Office (APO, FPO, and DPO)

USPS provides flat-rate shipping service to military post offices like the Army or Air Force Post Office (APO), Fleet Post Office (FPO), and Diplomatic Post Office (DPO). 

Remember that you’ll need a customs form when shipping to these military post offices. You can fill out the form online by visiting the USPS website. 

Also, you should address the package to a specific person in the military installation. 

For Businesses

Businesses, especially eCommerce and online stores, would benefit highly from the flat-rate shipping options provided by shipping companies like USPS. 

Priority Mail Regional Rate

As mentioned, the Priority Mail Regional Rate service is a shipping option where prices are based on the distance traveled, not the item’s weight and size, to reach the recipient. The key benefits of the regional rate are speed and savings. 

Regional rate boxes may be best if you send small yet heavy items over a short distance. 

Priority Mail Open and Distribute

You can use PMOD (Priority Mail Open and Distribute) for bulk mailings. This service allows customers to ship items in an approved USPS container to an authorized USPS location. The container is opened, and its content is delivered to the final destination. 

If you need to coordinate with a local post office when using the Priority Mail Open and Distribute service or any USPS service, visit FindPostOffice.org. You can access useful post office information through our website. 

FAQs (Frequently Asked Questions)

  1. Does the USPS flat rate include international shipping?

Yes, it does. USPS provides flat-rate shipping services to international destinations in over 190 countries. 

When shipping internationally, one must consider the destination country’s regulations on things that can be imported into the country. 

  1. What about shipping labels?

Shipping labels are essential documents you place on a package to inform the courier company where to deliver the package. USPS users can create a shipping label at the post office or via Click-N-Ship. 

  1. Are flat-rate shipping prices cheaper than standard shipping prices?

Flat-rate shipping is cheaper for eCommerce businesses that regularly ship orders over long distances. If this is the case, flat-rate shipping is cheaper than standard shipping. However, flat-rate shipping may not be the money-saving option for businesses that don’t have regular shipping schedules. 

  1. Is standard or flat rate shipping faster?

Generally speaking, flat-rate shipping is faster than standard deliveries. For instance, USPS Priority Mail Flat-Rate shipping takes one to three business days to deliver a package. Coupled with this speedy delivery is a streamlined shipping process made possible by the flat-rate shipping prices.


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