What is USPS Priority Mail Cubic?

Let’s learn about the benefits of Cubic pricing and how the service works

  • Written by Matt Holman
  • Published on July 7, 2020
  • Time to read 9 minutes

It’s Cheap to Be a Cube

Every industry has its little annoyances. You know, those aspects you wish you didn’t have to deal with, the ones your friends in other verticals hear about and say, “Sure am glad I don’t have to deal with that.” That frustration can turn to gratitude very quickly, however, with the right motivation.

Let’s pick a random example, such as…brick-and-mortar retail vs. e-commerce. It’s pretty easy to imagine e-commerce brands envying their retail relatives in the physical realm when it comes time to charge users shipping fees and customers abandon their carts.

That dynamic might invert itself if, hypothetically, worldwide circumstances are arranged in a manner that either compels or impels large percentages of the human race to do as many daily activities from home as possible.

In such an environment, retailers, great and small, would likely find that if people can’t do it online, they won’t do it at all and that shipping fees are only a secondary concern.

Such a situation—should it ever come to pass in our lifetimes—would, however, make the cost of shipping a central point of competitive advantage. Brands that can charge less for shipping will earn more market share, and those that can reduce their shipping overhead will maximize profits.

But how, exactly, can e-commerce brands capitalize on that without Amazon-level budgets and infrastructure?

The same way you win a poker game against a cheater: with an Ace up your sleeve.

Priority Mail Cubic—The Shipper’s Secret Weapon

There is a little-known shipping program that the USPS offers for packages under 20 pounds that can meet certain size restrictions. It’s cheaper and faster than other shipping methods for qualifying parcels, but most e-commerce retailers either don’t know about it or don’t use it.

So, what is this mystical gateway to delivery delightfulness? It’s called Priority Mail Cubic, or just “Cubic” for short. It’s a unique service the USPS offers, and it can do wonders for reducing shipping overhead for your business.

With Cubic, your business gets charged based on the dimensions of your package, not its weight. It’s an excellent alternative to FedEx and UPS if you want to save the most money on shipping, as it’s just as fast (if not faster), and you don’t have to stress about package weight as long as it’s under the 20-pound limit.

Let’s take a closer look at how it works. The trick is to use software that offers this incredible service at the correct rate (some shipping platforms mark this up to make more money).

Let’s learn about the benefits of Cubic pricing and how the service works.

How USPS Priority Mail Cubic Works

The Requirements

In order to avail yourself of Cubic shipping, your package has to meet specific criteria, so before we explain how to calculate costs or what savings you can expect, we should determine whether your shipments are candidates for the program.

Cubic parcels must match the following three attributes:

  • Weight—less than 20 pounds
  • Volume—0.5 cubic feet or less
  • Size—no dimension longer than 18 inches

If your shipping meets these precise specifications, it can be shipped via Priority Mail Cubic.

Determining Postage

The reason Cubic is such an effective tactic for reducing shipping costs is because of its unique pricing method that doesn’t take into account the weight of the package. As long as it’s less than 20 pounds, the USPS doesn’t give a ship what it weighs. If that’s the case, though, how do you determine shipping prices?

Well, it takes a little bit of math. So dig your old algebra notes out of the trunk; you might need them.

Here are the steps you need to take to calculate your package with Cubic:

  1. Measure the length, width, and height of your package. Round each dimension down to the nearest quarter inch. For example: 3 x 10 x 12 package
  2. Multiply the dimensions (Height x Width x Length) and divide that number by 1728. For example: 3 x 10 x 12 = 360 / 1728 = .2083
  3. The decimal you get back is the size of your package in “cubic feet.”
  4. Finally, round up your cubic feet measurement to .1, .2, .3, .4, or .5. For example: .2083 rounds up to .3

After you’ve done all that number crunching, you can compare the final cubic feet measurement against the USPS’s pricing tables (which you can find below, up to date with pricing for 2022). Determining the price is simply a matter of matching the cubic measurement to the number of shipping zones the package will have to travel. And that’s it.

Benefits of USPS Priority Mail Cubic

First and foremost, Cubic pricing means weight doesn’t come into the equation, allowing you to ship cheaply when your package is less than 20 lbs and is smaller than .5 cubic. Beyond that, though, USPS Priority Mail Cubic pricing offers many benefits you won’t find from other carriers. These include:

  • Fast Delivery Within 1 to 3 Business days: USPS’s Priority Mail Cubic service makes it possible to ship your items to customers within 1 to 3 days across all states in the USA.
  • Free Package Tracking: USPS will offer free package tracking on shipments so you can follow the journey of your product.
  • Reduced Shipping Costs: With Cubic, you get much more competitive rates than other shipping methods.

“That’s great!” you might be saying. “If it’s so easy to ship cheaply, though, why doesn’t everybody do it?”

That, dear reader, is, as the Bard would say, “the rub.”

Cubic Shipping Caveats (and How to Get Around Them)

Caveat #1: The Threshold

Cubic offers you the possibility to save big on all of your shipping. What makes it difficult is that the USPS won’t let just anyone ship Cubic. To get these special rates from your friendly neighborhood postman, you have to meet a certain order volume threshold.

Think of it as a minimum order value to qualify for free shipping. Except, instead of “free,” it’s just “much cheaper,” and instead of $30 in product, it’s 50,000 packages a year.

This requirement prevents everyone and their mother from shipping holiday gifts to faraway families using Cubic pricing. Unfortunately, it also prevents smaller retailers from doing the same, at least unless they have help.

Solution #1: The Inside Man

Okay, so you’ve found your secret weapon, but you need some help putting it to use. So, you do what any sensible individual would: you find yourself a wingman who will put in a good word for you. Though, in this case, it’s not necessarily a wingman, but a wingbrand.

Several solutions can help you bridge this volume gap, and there are some names to call them by. They go by titles such as “shipping aggregators,” “independent postage vendors,” and “online postage providers,” just to name a few.

But while there are variations on the business model or services provided, the base functionality is the same: they allow you to print your own postage and shipping labels.

This particular industry niche began as a way to save businesses a trip to the post office or other drop-off locations. As it grew, however, additional core features were added to make the service more beneficial and to give the brand offering it a competitive edge.

These included features like reduced shipping rates (resulting from the vendor/aggregator’s brokered deals with the carriers), API integrations to calculate and populate shipping costs automatically, and more.

We could go on and on here (and we have, in fact, in other places), but what’s relevant to the current discussion are the agreements with shipping carriers. These arrangements allow aggregators to treat an entire lot of shipments with a given carrier, made using their system in a given year, as coming from a single business entity.

In other words, the shipments are “aggregated” together, and it’s easier for ten retailers using a single aggregator to ship 5,000 packages each to break that limit of 50,000 than it is for any of them to do alone.

This is what a solution like this can offer: convenience and improved shipping rates. But not every brand approaches the task of passing on the savings to your business with the same philosophy.

Caveat #2: The Grift That Keeps on Giving

It’s essential to be aware that not all third-party shipping software offers Cubic as an option. For those that do, it’s not always the actual Cubic pricing they offer. Here’s what we mean.

The USPS offers the Cubic program because they want to reward shippers for using smaller packages (making it easier for them to ship more in fewer trucks/planes/etc.). That’s why the pricing is better. And they work with vendors and aggregators to offer the rates because it gets more shippers in line with those requirements.

Obviously, businesses in this space are, well, businesses, meaning they intend to turn a profit (as opposed to, you know, non-profits). So, almost every solution will either charge a fee or mark up the Cubic rates to generate revenue from offering those rates to their clients (and eHub is no exception).

But both as business professionals and as consumers, we are all well aware that there’s a difference between an equitable exchange and scalping.

Some brands mark up their Cubic prices more than others, obviously. But keep in mind here: this is an offering that requires effectively zero overhead.

Unlike product brands, which can market themselves as a “premium” brand off of the ostensible promise of products built with better materials, design, and engineering (no matter how flimsy that excuse might be—looking at you, Apple), these brands are only offering access to reduced shipping costs, so excessive markups aren’t warranted.

Solution #2: Second Opinions to Avoid Second-Rate…Rates

This may seem an obvious solution, but it’s hard to overstate its relevance or efficacy. Never be afraid to exercise your right to shop around—even in B2B arrangements—especially here.

The USPS doesn’t publicly list their cubic shipping rates, so you’ll have to do some good, old-fashioned price matching on this one. While we mentioned above that everyone using Cubic is essentially getting the same “product,” there are variances in the level of customer support you’ll receive from different solutions, not to mention how easy support is to contact.

Beyond that, what determines the value of a lot of these solutions (and which clients are happy with their service) are the available API integrations. There’s no universal solution, so your best bet is to look for one that offers the integrations that are most critical for your business or find one with a team willing to prioritize building the functionality you need.

So, look for positive reviews and ratings, check with your peers in the e-commerce industry for referrals, and ask any hard questions you can think of so you can find a provider that meets your brand’s unique needs.

The Nitty-Gritty: USPS Cubic Pricing

Cubic Pricing Tiers

Now that we’ve covered the what, the why, and the who, let’s talk about the “how”—as in, “how much?”

Regarding Cubic feet measurement, your package will fall into one of five tiers that USPS uses to calculate the shipping rate. Here is what each tier consists of:

  • Tier 1: Packages up to .10 cubic feet
  • Tier 2: Packages more than .10 and up to .20 cubic feet
  • Tier 3: Packages more than .20 and up to .30 cubic feet
  • Tier 4: Packages more than .30 and up to .40 cubic feet
  • Tier 5: Packages more than .40 and up to .50 cubic feet

These tiers don’t change year-to-year, so regardless of fluctuations in actual pricing, a given size of the package will always be the same tier.

2022 USPS Priority Mail Cubic Rates

Cubic Ft. Range Up To:
L, 1 & 2$7.54$8.02$8.25$8.37$8.50
Zone 3$7.81$8.20$8.62$8.85$9.07
Zone 4$8.05$8.49$9.01$9.57$10.04
Zone 5$8.37$9.12$10.03$11.83$13.18
Zone 6$9.18$10.96$13.48$15.92$17.79
Zone 7$9.77$11.62$15.22$18.73$22.31
Zone 8$10.43$12.67$17.93$21.59$25.74
Zone 9$18.56$25.09$34.46$42.67$51.21

The rates, on the other hand, tend to change on an almost yearly basis. How much you’ll pay depends on your cubic dimensions (the tiers mentioned above) and zoning—including the zone of origin, the destination zone, and the number of zones in between.

Here’s a table of what the 2022 rates for USPS Priority Mail Cubic look like to give you an idea:

How You Can Get Started With Priority Mail Cubic

There’s one more “how” to answer here: “How do I get started?”

The best way to start with Cubic is to find an appropriate vendor or aggregator and integrate their shipping app or API into your fulfillment process. We should warn you, however, that since Cubic is a relatively unknown program, it’s hard to find a platform that offers favorable pricing, let alone the shipping option itself.

Even some of the most popular tools, such as Shipstation, don’t offer commercial-level pricing for Cubic, so don’t decide on brand visibility alone.

We won’t pretend that we’re a perfect fit for every e-commerce retailer or 3PL outfit, but at eHub, we build our pricing structure so that we profit with you, not from you. In other words, if maximum access to the discounts of Cubic shipping is a significant factor in your decision, we’re probably worth a look.

Wrapping Things Up

For brands that constantly battle to keep shipping costs manageable, discovering Priority Mail Cubic can feel like pulling a magic sword from a stone pedestal or picking up an enchanted Norse hammer. Sadly, most brands don’t know about said mystical weapon of shipping supremacy, or if they do, they don’t think they can qualify.

While we can’t qualify you to sit on the throne of Asgard or claim the crown of England, we can help you significantly reduce your shipping costs (which is almost as good).

So, if you’d like to know more about the program or how it can save you 15% on car insurance shipping fees, give us a call.

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