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.
Determine which of the three dimensions of the package is the longest. If is not immediately obvious, measure each side to determine this.
Take a measurement of the longest side with the tape measure and write it down. This is the length of the package.
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.
Add together the length and the girth for your final length plus girth measurement.