Package Dimension Rounding for UPS and USPS

[loose_goose_garage]

I've always rounded up my measurements, for example whether it was 12.1" or 12.9", I would put 13".

After reading another post, it got me wondering and I did some searching:

From the UPS Site: 

• Round Up
  Round to the nearest whole number when taking your measurements. For example, 1 to 1.49 will be considered 1, and 1.5 to 1.99 will be considered 2.

However for USPS, there's is a bit more difficult to navigate for what we use here on eBay:

Their example: A box measures 20.75" x 20.25" x 20"

Priority Mail dimensional weight for rectangular shaped parcels to zones 1–9.

1. Measure the length, width, and height in inches. Round off 1 each measurement to the nearest whole inch (length = 21, height = 20, and width = 20)

But this is under Retail- Priority Mail page.

I cannot find anything under Ground Advantage that has this type of information. Does it follow the same rule?

[nobody*s_perfect]

Yes, Ground Advantage follows the same dimensional rounding as Priority. See section 1.4.2:  https://pe.usps.com/text/dmm300/283.htm

The exception for both services is measurements for USPS Cubic rates, which round down to the nearest 1/4 inch. Just to keep things interesting.

1.3.3 Determining Cubic Tier Measurements for Rectangular and Nonrectangular Parcels

Follow these steps to determine the cubic tier measurement for rectangular and nonrectangular parcels:

1. Measure in inches the length, width, and height at each dimension’s maximum point. Round down (see 604.7.0) each measurement to the nearest 1/4 inch. For example, 6-1/8" x 5-7/8" x 6-3/8" is rounded down to 6" x 5-3/4" x 6-1/4".
2. Multiply the length by the width by the height and divide by 1,728. Example: 6" x 5-3/4" x 6-1/4" = 215.6 divided by 1,728 = 0.125. This piece exceeds 0.10 Tier 1 threshold. It is calculated at Tier 2: 0.101 to 0.20.

1.3.4 Determining Cubic Tier Measurement for Soft Pack and Padded Envelopes

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. Pleated (e.g., expandable) mailpieces must meet the measurement guidelines in 1.3.3 to be eligible for cubic pricing. Determine cubic-tier measurements as follows:

• Measure the length and width separately in inches.
• Round down (see 604.7.0) each measurement to the nearest 1/4 inch. For example, 10-1/8 inches is rounded down to 10 inches.
• Add the two measurements together. The maximum total of length plus width must not exceed 36 inches. See Exhibit 1.3.4 for corresponding price tiers.

https://pe.usps.com/text/dmm300/283.htm

Cubic for Priority is similar, bt with a size limit of .5 cubic foot:  https://pe.usps.com/text/dmm300/223.htm