You’ve seen dynamic pricing before. Airline fares shift as departure approaches. Ride-share prices climb when demand spikes. 

Shipping follows a similar logic, but not quite in the same way. Most carrier changes are scheduled and announced rather than changing minute-to-minute. But carriers increasingly use demand-based surcharges and pricing formulas that can change what you pay. 

Each one needs a different response, so it helps to understand dynamic pricing and know what you’re looking at. 

How USPS manages dynamic pricing differently 

USPS typically builds temporary increases into the base price rather than adding a separate demand surcharge. USPS prices now change several times a year, in temporary, targeted, and structural ways. This can include time-limited increases, temporary peak season pricing, and formula changes that alter the amount you’re billed. 

The rates you see today might not match those you see next month. Planning around a single annual increase no longer makes sense. 

USPS is explicit about this. It calls its holiday increase a temporary price change rather than a surcharge. In its March announcement of an 8% time-limited increase, it drew a contrast with competitors by noting that other carriers had responded to rising costs with surcharges, while USPS has avoided them. 

According to USPS, the recent temporary increases cover transportation costs and extra holiday handling. Pricing that adjusts to those conditions, rather than waiting for one yearly reset, is the clearest sign of the shift. 

USPS publishes its price list; however, your rates in ShipStation reflect your account’s discount. Because the increase is built into the postage price rather than listed as a separate USPS surcharge, it can be easy to miss. Unless you’re comparing what you paid for the same shipment over time, you may only notice it in your monthly total. 

How UPS and FedEx show their changes 

UPS and FedEx take the more visible route. Both publish named, per-package demand surcharges that apply in addition to all other applicable charges. 

This season: 

  • UPS demand surcharges on Additional Handling, Large Package, and Over Maximum packages began September 27. Charges on UPS Ground Residential and eligible air services begin October 25 and run through January 16, 2027. See UPS’s Demand Surcharges for more details. 
  • FedEx surcharges for Additional Handling and Oversize took effect on September 28. Residential and express charges begin October 26 and run through January 17, 2027. See FedEx’s Demand Surcharges for more details. 

FedEx takes this a step further: its Demand–Residential Delivery Charge can adjust weekly based on a customer’s shipping volume and peaking factor. That’s a closer example of true dynamic pricing, because the charge can change based on current shipping activity rather than following a fixed seasonal rate 

Both carriers say the periods can change. Treat end dates as plans, not promises. 

The formula change that quietly raises your bill 

Peak pricing makes headlines. This one doesn’t. 

Effective July 12, USPS changed how it calculates dimensional (DIM) weight, the billable weight based on a package’s size, not its actual weight. For applicable competitive package products over one cubic foot, USPS now uses a 139 divisor, and each dimension is rounded up to the next whole inch. 

Here’s what that means. Take a coffee maker in a box measuring 12.25″ × 12.25″ × 12.25″ that weighs 5 lbs. Rounded up, the box becomes 13″ × 13″ × 13″, or 2,197 cubic inches. Divide by 139, and the billable weight is 16 lbs. 

What to do about it 

Here are four strategies to address dynamic pricing. 

1. Audit your packaging for dimensional weight 

This is one of the highest-impact fixes you can make, and it’s within your control. Pull your top 20 SKUs by USPS shipment volume, and run the new DIM calculation on each. Then right-size boxes where the math justifies it. 

Measure packed boxes, not products. A box a fraction of an inch over a whole-inch line can jump to the next size once rounded. Start with lightweight products in oversized boxes. They’re the most exposed to DIM weight, because the box drives the billable weight, not the product. 

2. Compare rates on every order, automatically 

When prices move, the cheapest service for a given package moves too. Checking by hand means comparing yesterday’s rates against today’s orders. 

A basic rate shopping tool only compares one or two carriers. But simply looking up a rate isn’t enough. 

A more impactful rate shopper tool compares available services across multiple carriers for each order and automatically selects the best option based on your rules. When prices change, the comparison updates with them in real time. 

3. Spread your volume across carriers 

If most of your volume relies on a single carrier, a single pricing change affects your entire shipping budget. Using multiple carriers gives you more opportunities to find competitive pricing and the flexibility to switch carriers if something goes wrong.  

Multi-carrier shipping also strengthens your hand when you talk to carriers. 

Compare options by the weight-and-zone combinations you actually ship. A lighter parcel might favor one, a heavier cross-country one another, and the answer can change by season. 

4. Track your shipping costs 

For UPS and FedEx, many demand surcharges appear as separate charges, so track them as their own line items rather than looking only at your total shipping spend. 

For USPS, where the increase is built into the price, check your label cost for the same shipment over time. Pick a handful of repeat shipments and compare them month to month. 

Manage the variable, not just the invoice 

Dynamic shipping rates don’t all look alike. UPS and FedEx show their changes as named surcharges. USPS builds its changes into the price itself. Either way, protecting margins means auditing packaging, comparing rates on every order, not depending on a single carrier, and watching your own numbers. 

The question isn’t whether carrier pricing will keep changing. It’s whether you’ll notice when it does. Start shipping with ShipStation today, and let rate shopping compare your options on every order so the next change doesn’t catch you off guard.

Todd Greenbaum
Todd Greenbaum
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