- Short answer
- Yes — Shopify Shipping lists USPS Cubic Pricing for Priority Mail and Ground Advantage, up to 20 lb and 0.5 or 1 cubic foot.
- Volume cap by service
- 0.5 cubic feet on Priority Mail, 1 on Ground Advantage; for packages, L × W × H (inches) ÷ 1728.
- Size limit
- Shopify: 18-inch side, 36-inch envelopes/soft-packs; USPS manual: 22-inch longest side. Neither, read September 23, 2026, says which one Shopify applies.
- Plan named for Cubic
- A 2019 changelog named Shopify and Advanced; no page we read on September 23, 2026 names one.
- International labels
- Shopify's USPS page, read September 23, 2026, doesn't say whether Cubic covers them.
- Who picks the rate
- Not described on the three pages we read on September 23, 2026; price your real box in the calculator.
Does Shopify Shipping offer Cubic pricing on your plan?
Shopify offers it on USPS labels. Shopify's USPS label page says, under USPS Cubic Pricing:
USPS offers discounted rates for packages, envelopes, and soft-packs on Priority Mail and Ground Advantage shipping services. If you typically send small and heavy products, such as weights or coffee beans, then consider using Cubic Pricing.
Shopify's 2019 changelog made Priority Mail Cubic pricing "available to merchants on the Shopify and Advanced plans." No page we read on September 23, 2026 — the USPS, rate-calculation and Basic plan pages, or Shopify's pricing page — names a plan for Cubic Pricing.
Shopify's rate-calculation page says label discounts "don't always change with your subscription plan"; our label-cost page covers whether yours does.
What packages qualify for USPS Cubic pricing?
Both services cap Cubic at 20 pounds; volume differs: 0.5 cubic feet on Priority Mail, 1 cubic foot on Ground Advantage. Rolls and tubes don't qualify. These are Cubic limits, not USPS label maximums.
Shopify's USPS page lists 18 inches a side for packages (36 for envelopes and soft-packs); USPS's Domestic Mail Manual says the longest dimension "must not exceed 22 inches." Neither, as read on September 23, 2026, says which limit applies when you buy the label in Shopify.
Shopify's international USPS section lists its own services, Priority Mail International among them, without mentioning Cubic. As we read it on September 23, 2026, Shopify's USPS page doesn't say whether Cubic covers international labels.
Shopify's formula for packages divides length × width × height in inches by 1728. Its example lists a 14 x 8 x 5-inch box at 0.4 cubic feet, under Priority Mail's 0.5; the division itself gives about 0.32, which USPS's manual places in its tier "more than .30 up to and including .40."
Does Shopify pick the Cubic rate for you?
None of the three pages we read on September 23, 2026 — the USPS, rate-calculation and shipping-labels overview pages — says whether Shopify applies the Cubic rate for you or what happens outside the limits.
Shopify's rate-calculation page says discounts "can vary based on the package type, weight, destination, and origin," and its calculator takes a saved package or Custom dimensions you enter. Price your real box in the calculator before repacking around Cubic.
This article was written entirely by AI under human editorial direction. The editor sets the topic and structure, runs multi-stage validation on facts, links, and interactive elements, and verifies the output is useful from a business perspective. All claims are checked against official Shopify sources. Details may change — always confirm critical data at shopify.com.
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