USPS cubic tier calculator (Ground Advantage – Commercial)

Eligibility (§1.2, §1.3.1)

• USPS Ground Advantage – Commercial prices only (including Ground Advantage Return service): PC Postage, USPS-approved IBI meters, permit imprint, or USPS Returns. Not available at retail counter prices.
• Every cubic piece – boxes, soft packs and padded envelopes – must be 1 cubic foot or less, weigh 20 lb or less, and the longest side must not exceed 22 in.
• Rolls and tubes cannot use cubic prices.
• DMM 283 §1.3.1 is marked [7-12-26] (current text in effect from July 12, 2026).

Boxes – rectangular and non-rectangular (§1.1d, §1.3.3)

1. Measure length, width and height in inches at each dimension’s maximum point.
2. Round each measurement down to the nearest 1/4 inch (12-3/8 → 12-1/4).
3. Length × width × height ÷ 1,728 = cubic feet. No 0.785 factor for cubic tiers.

Tier	Cubic feet (after rounding down)
0.1	up to 0.10
0.2	more than 0.10 up to 0.20
0.3	more than 0.20 up to 0.30
0.4	more than 0.30 up to 0.40
0.5	more than 0.40 up to 0.50
0.6	more than 0.50 up to 0.60
0.7	more than 0.60 up to 0.70
0.8	more than 0.70 up to 0.80
0.9	more than 0.80 up to 0.90
1.0	more than 0.90 up to 1.00

Soft packs and padded envelopes (§1.3.4, Exhibit 1.3.4)

Measure length and width of the original packaging, round each down to 1/4 in, and add them. Length + width must not exceed 36 in. Pleated (expandable) pieces must use the box method above.

Tier	Length + width
0.1	0 in up to 21 in
0.2	more than 21 in up to 27 in
0.3	more than 27 in up to 31 in
0.4	more than 31 in up to 34 in
0.5	more than 34 in up to 36 in

Compared with dimensional weight (§1.4)

If the parcel is priced by weight instead, Ground Advantage commercial parcels to Zones 1–9 over 1,728 in³ pay the greater of actual and dimensional weight: each side rounded up to a whole inch, ÷ 139, rounded up to the next pound (non-rectangular × 0.785 first; over 70 lb pays the 70 lb price). Because cubic rounds down and dimensional weight rounds up, a box can be cubic-eligible and still have a dimensional weight.

Not stated in the DMM: whether the 22 in limit is checked before or after the 1/4-inch rounding. This calculator checks the size as measured (22.1 in fails), which is the safer reading. The 1 cubic foot limit is checked on the rounded-down sides, the same numbers used for the tier.

Sources (checked 2026-10-30):

• USPS DMM 283 §1.1d, §1.2, §1.3 – Ground Advantage Commercial cubic pricing (soft packs: Exhibit 1.3.4; read in full 2026-10-30) [P9, official]

USPS Priority Mail Express, Priority Mail, Ground Advantage, Parcel Select (retail & commercial) – from Jul 12, 2026

Formula	If L × W × H (in) [× 0.785 if non-rectangular] > 1,728: ÷ 139 = lb
Rounding	Each side rounded up to the nearest whole inch (DMM 604.7.0); dimensional weight rounded up to the next whole lb. Above 70 lb the 70 lb price applies.
Applies to	Only parcels to Zones 1–9 whose volume exceeds 1 cubic foot (1,728 in³). Non-rectangular parcels: volume × 0.785 first.
Effective	From July 12, 2026 (DMM changes marked [7-12-26]; Postal Bulletin 22705).

• Zones 1–9 only.

Sources (checked 2026-10-29):

• USPS DMM 123 – Priority Mail (retail) [P1, official]
• USPS DMM 113 – Priority Mail Express (retail) [P2, official]
• USPS DMM 213 – Priority Mail Express (commercial) [P2, official]
• USPS DMM 223 – Priority Mail (commercial) [P3, official]
• USPS DMM 253 – Parcel Select [P4, official]
• USPS DMM 283 – Ground Advantage (commercial) [P4, official]
• USPS Postal Bulletin 22705 [P5, official]
• USPS Ground Advantage [P6, official]