You’ve probably noticed that your shipping bills have gone up in 2026, even though your packages haven’t changed. The main culprit isn’t the annual rate increase of 5.9% announced by FedEx, UPS, and Purolator. It’s a much more subtle change: the new rounding rule for volumetric weight, which will take effect in January 2026 at FedEx and UPS, and is already being implemented by most carriers.

This rule changes how every inch and every centimeter of your boxes is calculated. As a result, for many shipments, the billable weight jumps from 15 to 20 % per package, without having to ship anything heavier. For Canadian small and medium-sized businesses, particularly those that sell online or regularly ship internationally, the cumulative impact on profit margins can be significant.

In this guide, we break down exactly what has changed, why your costs are rising even with «standard» boxes, and how to adjust your packaging and negotiation strategies to regain control.

Specific gravity, in a nutshell

Carriers don't just charge based on a package's actual weight. They also calculate a bulk density (also known as dimensional weight or DIM) based on volume, and then use the higher of the two as billable weight.

The formula is simple:

• In inches (FedEx, UPS, Purolator): Length × Width × Height ÷ 139 = volumetric weight in pounds
• In centimeters: Length × Width × Height ÷ 5 000 = volumetric weight in kilograms

A light but bulky package—such as a pillow, a lampshade, or shoes in a large box—will almost always be charged based on its volume, not its actual weight.

What's changing in 2026: the rounding-up rule

Before 2026, many carriers accepted decimal measurements: an 11.1-inch side remained 11.1 inches in the calculation. Since January 12, 2026, at FedEx and the January 26, 2026 at UPS, any fractional amount is now rounded up to the next whole number before applying the formula.

In practical terms:

• 11.1 inches becomes 12 inches
• 8.01 inches becomes 9 inches
• 6.2 inches becomes 7 inches

This adjustment, applied to all three dimensions, transforms a package that measured 11.1 × 8.5 × 6.2 in as an «official» package from 12 × 9 × 7 in.. The billable volume increases from 585 cu. ft. to 756 cu. ft., an increase of 29 %. At a divisor of 139, the billable weight jumps from 4.2 lbs to about 5.4 lbs—a jump large enough to push it into the next rate bracket.

Why does this rule hurt so much?

There are three reasons why this rounding is a silent trap:

• It applies to every aspect. Just a half-inch margin on three sides can be enough to drive up the cost.
• He's not at the counter. Carriers scan and measure shipments themselves at the warehouse; adjustments are often made to the invoice days later.
• This is in addition to the other costs. Purolator fuel surcharge at 34,5 % In spring 2026, residential surcharge, «additional handling» surcharge: all charges are calculated based on the rounded billable weight.

The real cost for a Canadian SME

According to our calculations and several analyses published by leading North American integrators, the actual cost for an SME that ships 200 to 500 packages per month rises from 8 to 12 % in 2026, whereas the officially announced increase is 5.7 to 5.9 %. The difference stems precisely from rounding and the new thresholds for additional handling fees.

For daily shipments of «standard-sized» boxes (approximately 12 × 9 × 7 inches), a retailer could easily end up paying several thousand dollars more per year without changing a single product.

5 Practical Steps to Regain Control

1. Choose «round» cardboard boxes without any protruding edges

Since each measurement is rounded up to the nearest inch, the goal is to choose boxes whose exterior dimensions are already whole numbers. A box measuring 12 × 9 × 6 inches will be cheaper than a box measuring 11.1 × 8.5 × 5.5 inches, even though the latter appears smaller. Measure your boxes with a rigid tape measure and round off the measurements yourself before the carrier.

2. Adapt the format to the product, not the other way around

A large portion of avoidable costs comes from empty space. For clothing, flexible packaging (poly mailers) eliminates volumetric weight. For furniture or disassemblable items, flat-pack packaging can reduce dimensional weight by 30 to 50%. Invest in 3 to 5 master box sizes which cover 80% of your shipments.

3. Check for weight adjustments on your invoices

Carriers publish weight adjustments in a dedicated section of the portal. Review them monthly: measurement errors in the carrier’s favor often account for 2 to 4% of the total billed amount. If the same box is adjusted multiple times, dispute it with a photo and the official dimensions.

4. Negotiate the terms, not just the discounts

Discounts on published rates are no longer enough to offset the rounding. The real negotiation centers on the unit converter : Going from 139 to 166 or 194 can result in savings of 15 to 25 % across the entire account. With a broker or partner that aggregates volume, this is currently the most profitable strategy.

5. Compare carriers on a per-package basis

UPS, FedEx, Purolator, Canpar, and DHL do not apply the same rules across all regions. On certain Canadian routes, Purolator remains the most cost-effective option for light and bulky packages; for international shipments, DHL Express retains a clear advantage. A strategy multi-carrier allows each package to be routed to the least expensive service based on its actual billable weight.

Summary table: What has changed in 2026

Take control of your shipping costs

The changes in 2026 aren't catastrophic in and of themselves—they're mostly invisible. That's what makes them costly: as long as a company doesn't measure its actual billable weight and does not renegotiate its terms, the gap between published rates and actual costs will continue to widen.

At Shipping Store, we consolidate the shipping volumes of hundreds of Canadian SMEs to negotiate directly with major carriers: more favorable dimensional weight rates, capped surcharges, and automated monthly audits. The result, for most of our clients, is a savings of 20 to 40 % compared to counter rates—without changing carriers or software.

If your 2026 bills seem higher than expected, it’s not just your imagination. Request a free audit of your most recent shipments at expertshipping.ca and regain control over unit weight before it puts even more pressure on your profit margin.