---
title: "USPS Cubic pricing: which packages qualify (2026)"
description: "Ground Advantage Cubic: up to 1 cubic foot, 20 lb, 22 in. Priority Mail Cubic: up to 0.5 cubic foot. How boxes and poly mailers are tiered, with prices."
canonical: https://resellerindex.com/usps/rules/cubic-eligibility/
last_updated: 2026-10-19
publisher: "The Reseller Index"
---

# Which packages qualify for USPS Cubic pricing?

**Ground Advantage Cubic takes parcels up to 1 cubic foot, 20 lb and 22 inches on the longest side; Priority Mail Cubic takes up to 0.5 cubic foot with the same 20 lb and 22 in. limits.** Rolls and tubes don't qualify.

Cubic is a commercial price, available through PC Postage label services that offer it, not at the Post Office counter. Boxes are tiered by volume with each side rounded down to the 1/4 inch; poly mailers and padded envelopes by length plus width, up to 36 in.

Rates verified on Oct 19, 2026

Postage in the examples is from Notice 123 effective Oct 4, 2026, which includes USPS's temporary holiday prices for Ground Advantage and Priority Mail until 12 a.m. CT Jan 17, 2027. The fees quoted here are the same as in the July 12, 2026 edition, before the holiday prices began.

## The rule, in USPS's words

> “Each cubic mailpiece, including soft packs and padded envelopes under 1.3.4, must measure 1 cubic foot or less, weigh 20 pounds or less, and the longest dimension must not exceed 22 inches.”

[DMM 283.1.3.1](https://pe.usps.com/text/dmm300/283.htm), read Oct 19, 2026

> “Each cubic mailpiece, including soft packs and padded envelopes under 1.3.4 must measure .50 cubic foot or less, weigh 20 pounds or less, and the longest dimension must not exceed 22 inches.”

[DMM 223.1.3.1](https://pe.usps.com/text/dmm300/223.htm), read Oct 19, 2026

> “Round down (see 604.7.0) each measurement to the nearest 1/4 inch.”

[DMM 283.1.3.3](https://pe.usps.com/text/dmm300/283.htm), read Oct 19, 2026

> “Cubic-tier measurements for soft pack (poly, plastic, cloth, or similar soft packaging) and padded envelopes are based, in inches, on the outside dimensions of length plus width of the original packaging material.”

[DMM 283.1.3.4](https://pe.usps.com/text/dmm300/283.htm), read Oct 19, 2026

> “The maximum total of length plus width must not exceed 36 inches.”

[DMM 283.1.3.4](https://pe.usps.com/text/dmm300/283.htm), read Oct 19, 2026

## What it costs, with examples

*Boxes: tier = length x width x height (each rounded down to 1/4 in.) / 1,728. Ground Advantage online to Zone 5; prices from Notice 123 effective Oct 4, 2026.*

| Box (inches), weight | Cubic feet | Tier | Cubic price | Price by weight |
| --- | --- | --- | --- | --- |
| 9 x 6 x 4, 4 lb (a stack of paperbacks) | 0.125 | 0.20 | $9.92 | $13.89 |
| 6-1/8 x 5-7/8 x 6-3/8 (USPS's own example), 2 lb | 0.125 | 0.20 | $9.92 | $10.50 |
| 12 x 12 x 12, 15 lb | 1 | 1.00 | $18.68 | $22.90 |

*Poly mailers and padded envelopes: tier by length + width of the mailer as made (DMM 283.1.3.4). Online prices to Zone 5, Notice 123 effective Oct 4, 2026.*

| Mailer (inches) | Length + width | Tier | Ground Advantage Cubic | Priority Mail Cubic |
| --- | --- | --- | --- | --- |
| 10 x 13 | 23 | 0.20 | $9.92 | $14.02 |
| 12 x 15-1/2 | 27.5 | 0.30 | $11.51 | $17.41 |
| 14-1/2 x 19 | 33.5 | 0.40 | $13.48 | $21.98 |
| 19 x 24 | 43 | not eligible (over 36 in.) | pays by weight | pays by weight |

## Edge cases

- **Folding doesn't lower the tier:** a soft pack is measured by the outside size of the original mailer, not the folded-over size.
- **Expandable mailers** (pleated) are measured like boxes, by length x width x height ([DMM 283.1.3.4](https://pe.usps.com/text/dmm300/283.htm)).
- **Rounding goes down for cubic** but up for dimensional weight: 6-1/8 in. counts as 6 in. for the cubic tier and as 7 in. for dimensional weight.
- **Fees still apply:** Notice 123 lists the $4.50 characteristics fee and the HAZMAT fees under both cubic price tables.
- **Over a limit** (more than 20 lb, 22 in. or 1 cubic foot), the parcel pays by weight, and by [dimensional weight](https://resellerindex.com/usps/rules/dimensional-weight/) over 1 cubic foot.
- **Since July 12, 2026:** the longest side allowed rose from 18 to 22 in. and soft packs moved to five tiers ([tracker entry](https://resellerindex.com/changes/usps/2026-07-12-usps-ground-advantage-cubic-soft-packs/)).
- **Packing clothes and other soft goods:** soft goods from 5 to 20 lb must be packed in material with at least a 70-lb outer-ply basis weight, boxes of soft goods up to 5 lb must be filled to capacity, and shrinkwrap alone isn't acceptable ([DMM 601.3.9](https://pe.usps.com/text/dmm300/601.htm)).

## What to do

- For small, heavy items (books, tools, media), price the smallest box at cubic before paying by weight: the 9 x 6 x 4 in. example saves $3.97 to Zone 5.
- Pick the smallest mailer the item fits; an inch less in length plus width can drop a tier.
- Use a label service that offers cubic prices; the counter doesn't sell them.

## Questions

### Can I get USPS cubic pricing at the Post Office?

No. Cubic prices are commercial prices for PC Postage and permit customers ([DMM 283.1.2, 1.3](https://pe.usps.com/text/dmm300/283.htm); [DMM 223.1.3](https://pe.usps.com/text/dmm300/223.htm)).

### What is the weight limit for USPS cubic?

20 lb for both Ground Advantage Cubic and Priority Mail Cubic ([DMM 283.1.3.1](https://pe.usps.com/text/dmm300/283.htm), [DMM 223.1.3.1](https://pe.usps.com/text/dmm300/223.htm)).

## Related rules

- [How does USPS dimensional weight work?](https://resellerindex.com/usps/rules/dimensional-weight/) Over 1,728 cubic in., USPS bills the greater of actual weight and L x W x H / 139, each side rounded up first.
- [When does a padded envelope count as a package instead of a large envelope?](https://resellerindex.com/usps/rules/padded-envelope-flat-or-parcel/) Large envelope prices only up to 15 x 12 x 3/4 in., flexible and evenly thick (1/4 in. variance); otherwise parcel prices.
- [Does USPS round up package weight?](https://resellerindex.com/usps/rules/weight-rounding/) Ground Advantage steps at 4, 8, 12 and 15.999 oz, then whole pounds; any fraction rounds up. Priority Mail rounds up to the pound.
- [Why does USPS charge extra for a poster tube, tin or wooden box?](https://resellerindex.com/usps/rules/tube-can-wooden-box-fee/) $4.50 for tubes and rolls, cans, wood or metal boxes, and parcels with more than 24 oz of liquid in glass.

In the change tracker: [Ground Advantage Cubic: poly mailers move to cheaper tiers, and boxes up to 22 in. now qualify](https://resellerindex.com/changes/usps/2026-07-12-usps-ground-advantage-cubic-soft-packs/)

Also on this site: [Ground Advantage Cubic prices](https://resellerindex.com/rates/ground-advantage-cubic/)

[All 25 USPS package rules](https://resellerindex.com/usps/rules/)

## Sources

Rates verified on Oct 19, 2026 from each official page below.

- [USPS Notice 123, Price List (effective Oct 4, 2026)](https://pe.usps.com/text/dmm300/Notice123.htm)
- [USPS Domestic Mail Manual 223: Priority Mail commercial prices and eligibility](https://pe.usps.com/text/dmm300/223.htm)
- [USPS Domestic Mail Manual 283: Ground Advantage commercial prices and eligibility](https://pe.usps.com/text/dmm300/283.htm)
- [USPS Domestic Mail Manual 601: mailability, packaging and USPS-produced packaging](https://pe.usps.com/text/dmm300/601.htm)

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---

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