FedEx, USPS & UPS Dimensional Weight Calculator (+ Ecommerce Shipping Tips)
Meaghan has provided content and guidance for indie retailers as the editor for a number of retail publications and a speaker at trade shows. She is Fit Small Business’s authority on retail and ecommerce.
Katie-Jay aims to put answers in the hands of small business owners by leveraging over 10 years of retail and hospitality experience. With a background in gemology, she specializes in jewelry and luxury ecommerce.
This article is part of a larger series on Retail Management.
Dimensional weight—also called DIM weight—is a formula shipping companies use to determine shipping rates based on a parcel’s volume. It can result in large, lightweight parcels costing more to ship than small, heavy parcels.
Use the calculator below to determine the DIM weight of any parcel by entering the outside dimensions of the package. For irregular packaging, measure from the widest points.
How DIM Weight Works
Dimensional weight represents the amount of space your parcel occupies in relation to its actual weight. In most cases, carriers will consider the two weights and calculate rates based on whichever is greater. This greater value is called the billable weight.
Read on to learn more about how DIM weight is calculated, how it affects pricing, and when shipping companies use it.
Dimensional Weight Formulas
Dimensional weight is calculated by multiplying the package’s length, width, and height and then dividing the product by the DIM divisor—which is 139 (for FedEx and UPS) or 166 (for USPS).
DIM Pricing
When this value is factored into pricing, it’s commonly called DIM pricing. DIM pricing benefits carriers because it accounts for the amount of space each parcel occupies on the truck, boat, or aircraft.
Larger parcels allow for fewer units to fit in a single truckload, so they are more expensive to ship than small, heavy parcels.
If your business ships regularly, understanding how dimensional weight affects your bottom line is crucial to your success. Because of DIM pricing, you can dramatically overpay when shipping if you aren’t careful about your packaging choices. For instance:
Dimensional Weight of Parcels in Different Boxes
Box Type |  |  |  |
Dimensions | |||
| Actual Weight | 3 lbs. | 3 lbs. | 3 lbs. |
Dimensional Weight (UPS and FedEx) | 1 | ||
Billable Weight (Greater value of the two) | |||
Ground Shipping Cost (Houston to NYC) | $18.59 | $20.85 | $45.14 |
As you can see, the size of your packaging greatly impacts your shipping costs due to dimensional pricing.
Using our dimensional weight calculator above, you can quickly compare the DIM weights of different box options to determine the most cost-effective packaging for the items you ship.
You can also use it to see if large, lightweight items will still maintain a sufficient profit margin once you factor in dimensional weight shipping cost.
When DIM Weight Applies
UPS and FedEx factor in dimensional weight to calculate rates for all domestic and international shipments.
USPS, on the other hand, only uses dimensional weight for packages that fit all of the following criteria:
- Shipping via Priority Mail or Priority Mail Express
- Larger than 1 cubic foot (or 1,728 cubic inches)
- Shipping to Zones 5-9 based on your location (see your USPS Zone Chart here)
Additionally, DIM weight does not apply to USPS Priority Mail International items.
Not sure which carrier to use? Read our guide to FedEx vs UPS vs USPS for small businesses.
Tips for Ecommerce Shipping in 2022
With dimensional pricing in mind, here are six ways to minimize your shipping spend, increase your bottom line, and get orders out to customers faster:
Consider Product Size
In today’s competitive ecommerce environment, charging customers the actual cost of shipping usually leads to abandoned carts and lost sales. So you’ll likely have to find ways to offer free shipping on your products—which may mean absorbing some of the shipping costs on large products.
In these cases, large and low-cost goods might not yield enough profit to cover your losses.
Plus, you have to get those goods into your fulfillment warehouse and then ship them to your customers—which can be costly since DIM weight usually applies to both inbound and outbound shipments.
Ultimately, the overall packed size of a product is something you must consider when sourcing wholesale goods or manufacturing your own.
Choose Packing Materials Wisely
Now that you understand how DIM weights impact the price you pay for every parcel you ship, it’s time to closely scrutinize the boxes and mailers you use.
If you’re a budget-conscious small business or startup, your goal is to use the smallest box (or envelope, flat, or tube) needed to protect your item in transit. Anything more than that will cut into your bottom line.
Plus, too-large packaging requires excessive packing materials to fill the void, which adds costs. Using appropriate packaging to ship your products is an easy way to cut wasteful spending on fill materials and shipping rates.
Consider Custom Boxes
If you ship in volume and find that ready-made boxes aren’t a perfect fit for your items, custom-made boxes can help you save on shipping in the long run. This is especially true for shipping large items—like furniture or musical instruments.
For small items that ship in boxes less than 16”x16”x16”, you’ll find plenty of ready-made box options. But as the size you need exceeds those dimensions, your options start to thin.
Because of DIM weights, using even a slightly too-big box can dramatically increase your shipping rate on every order. Ordering custom-made packaging is an elegant solution to reduce your shipping outlay.
Explore Flat-rate Boxes
FedEx and USPS both offer a flat-rate option with rates based solely on the type of box you use. In these cases, weight doesn’t apply—which yields the USPS slogan for the program: “If it fits, it ships.”
These flat-rate boxes aren’t a good choice for every shipper. But if you sell small and heavy items, flat-rate boxes can provide a substantially lower rate. Plus, you don’t have to pay for boxes since they’re provided with the service.
See available flat-rate boxes in the FedEx One Rate and USPS Flat-Rate Priority Mail programs.
Compare Carrier Rates
If you manage any volume of ecommerce shipping and handling, you can save significantly by simply comparing shipping rates among the different carriers for every package you ship.
Most shipping software tools make both rate and time-in-transit comparisons fast and easy. That way, you know you’re getting the best possible rate on every package you ship, while providing the fastest service to your customers.
Our top recommendation for small-business shipping software is ShippingEasy. It compares rates in real time across multiple carriers, helps you manage your orders, automates labor-intensive tasks, and provides deep discounts on UPS and USPS rates. Plans start at $5, but visit ShippingEasy for a free one-month trial.
Factor in Surcharges
Both FedEx and UPS have a range of surcharges that can be tacked onto your published rates.
These include residential delivery surcharges, fuel surcharges for certain areas, Saturday delivery fees, and extra fees for oversized packages more than 96 inches long (or 130 inches in combined length and girth).
For a closer look at the current rates and surcharges (and how they affect your shipments), check out: FedEx’s 2022 Rates & Surcharges and UPS’s 2022 Revised Rates for Surcharges
Bottom Line
Whether you ship occasionally or daily, dimensional weight matters to your business. If you primarily use FedEx and UPS, every parcel you ship is subject to dimensional weight—which means every extra inch of packaging that you ship costs you more.
When shipping with these carriers, it’s a good idea to run every parcel through a dimensional weight calculator to get the billable weight based on box size.
To reduce your shipping outlay even further, consider DIM weight when sourcing goods, choosing packaging, using rate comparison software, and factoring in surcharges.
