Girth generally refers to the distance around an object. For example, the girth of a person is the distance, or circumference, around his waist. Girth is also used in shipping to determine how much a package will cost to ship. In this case, the dimensions must be measured to find the girth. If your subject is generally cylindrically shaped, such as pipe or a person, use the measuring tape to find the distance around the person at the widest point. The measurement is the girth.

1. If your subject is generally cylindrically shaped, such as pipe or a person, use the measuring tape to find the distance around the person at the widest point. The measurement is the girth.

2. For a rectangular prism, measure the length, width and height. The length is the longest dimension.

3. Use the following formula to calculate girth where W is the width and H is the height:

Girth = 2(W + H)

For example, if you had a box that measure 5 inches by 8 inches by 12 inches, 12 inches would be the length. Add 5 and 8 to get 13 and then multiply by 2 and you get 26 inches. This is the girth.

How to Determine Shipping Girth on Boxes

Most shipping services charge extra to deliver unusually large packages. For example, United Parcel Service (UPS) imposes an Over Maximum Limits charge on packages with over 165 inches in combined length and girth. The United States Postal Service (USPS) also charges in certain cases based on such criteria. If you want to ship your package via the most economical service, it’s important that you can accurately measure your package size.

1. Place the box on a table, right side up.

2. Measure the width. This is the shortest side of the package. UPS and USPS specify to round to the nearest inch. (Other shippers could specify differently.) For example, round 10.75 inches up to 11 inches and round 10.25 inches down to 10 inches.

3. Multiply the width by two. In the above example, if we measure 11 inches, then 11 x 2 = 22 inches.

4. Measure the height. This is the second-shortest dimension. Round to the nearest inch. For example, round 18.25 inches to 18 inches.

5. Multiply the height by two. For our example, 18 x 2 = 36 inches.

6. Add the results of Steps 3 and 5 to obtain the package’s girth. In our example, 22 + 36 = 58 inches.

How to Calculate Length Plus Girth

Length plus girth is a commonly used shipping measurement. Many shipping companies and mail services, both public and private, use a measurement standard to determine whether a package falls under the maximum size limitations for the carrier. This measurement, called “length plus girth,” can be done at home with a tape measure, and involves nothing more than adding the measurements of the longest side to that of girth, or distance around, that package.

Once you have calculated the length plus girth figure for your parcel, you can check it against the shipping requirements for your selected carrier.

1. Determine which of the three dimensions of the package is the longest. If is not immediately obvious, measure each side to determine this.

2. Take a measurement of the longest side with the tape measure and write it down. This is the length of the package.

3. Stand the package up so the longest side, the one you just measured, is vertical. Wrap the tape measure around the package, almost as if you are hugging it, and measure the distance around the package. In this way, you measure the girth, or the distance around the other sides of the package, leaving out the length.

4. Add together the length and the girth for your final length plus girth measurement.