USPS Oversized Package Rates | Overview

When shipping oversized packages via USPS, you may pay a higher rate. These rates take into account the overall size of the package rather than the weight. USPS uses dimensional (DIM) weight to accommodate lighter packages that take up extra cargo space. USPS considers oversized packages to be over 108 inches but not more than 130 inches in combined length and girth.

USPS Flat Rate packaging and Regional Rate boxes are excluded from using dimensional weight.

Dimensional price rules:

Dimensional price applies to low-density USPS parcels that meet these guidelines:

Packages that qualify for dimensional pricing will be assessed using the higher of these two rates:

  • Actual weight rate
  • Dimensional weight rate

Calculating dimensional weight:

To make this determination, USPS assigns a "dimensional weight" to each package. For these large and lightweight shipments, USPS will determine if the actual weight rate or if the dimensional weight rate is higher. The higher of the two will be the postage price.

The parcel shape determines how dimensional weight is calculated.

Rectangular parcels:
  1. Measure the length, width, and height in inches. Round off each measurement to the nearest whole inch.
    For example: 20.25" rounds down to 20 inches, 20.75" rounds up to 21 inches.
  2. Multiply the length by the width by the height:
    L x W x H = Volume in Cubic Inches
  3. If the result is equal to or greater than 1,728 cubic inches, divide the result by 166.
    (Volume in Cubic Inches)/166 = Dimensional Weight
    Round up to the next whole number to determine the dimensional weight in pounds.
    If the volume is less than 1,728 cubic inches, then USPS will use the Actual Weight to determine the postage cost.
  4. Use the dimensional weight to find the postage cost on a USPS rate table. Find USPS' published rate tables.
Non-rectangular parcels:
  1. Measure the length, width, and height in inches at their extreme dimensions. Round off each measurement to the nearest whole inch.
    For example: 20.25" rounds down to 20 inches, 20.75" rounds up to 21 inches.
  2. Multiply the length by the width by the height:
    L x W x H = Volume in Cubic Inches
  3. Multiply the result by an adjustment factor of 0.785:
    Volume x 0.785 = Adjusted Volume in Cubic Inches
  4. If the result is equal to or greater than 1,728 cubic inches, divide the result by 166.
    (Volume in Cubic Inches)/166 = Dimensional Weight
    Round up to the next whole number to determine the dimensional weight in pounds.
    If the volume is less than 1,728 cubic inches, then USPS will use the Actual Weight to determine the postage cost.
  5. If the dimensional weight exceeds 70 pounds, the mailer pays the 70-pound price.
  6. Use the dimensional weight to find the postage cost on a USPS rate table. Find USPS' published rate tables.
Was this article helpful?
2 out of 7 found this helpful

Comments

Add a Comment

Please sign in to leave a comment.