# How to Calculate Box Girth for USPS

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Is your business preparing to ship an odd-sized parcel, such as a piece of used machinery, or are you mailing a large box of wholesale merchandise to a key client? In either case, you will need to measure the package to determine the shipping options available to your business. Box girth is a key measurement when determining shipping charges. The sum of length plus girth will also dictate the appropriate shipping categories for a package via the U.S. Postal Service (USPS).

## Measuring Girth

Start by identifying the longest side of your package. The side perpendicular to the longest side is then measured for girth. If geometry isn't your forte, picture a box as a skyscraper. The outer tall edge of the building is your long side. The girth measurement is the perimeter (the sum of all four sides) of the base of the ground floor or top floor.

## Calculating for Shipment

The USPS imposes maximum sizes for packages. For standard shipments, the combined measurement of the longest side and the girth cannot exceed 108 inches. By paying a nonmachinable surcharge on the parcel, you can increase the size to a total of 130 inches in combined length and girth. Keep in mind that many larger parcels are also heavier, and weight limits are also imposed. The maximum weight for a standard parcel is 25 pounds and 35 pounds for a nonmachinable parcel. If your business is books, however, the media mail parcel class allows the shipment weight up to 70 pounds.