Be sure to jot down the measurements you take on a scrap piece of paper so you can refer back to them later. The length will be the largest measurement on the majority of packages. Many shipping serves only handle packages of up to a certain size, which is typically noted in whole inches.
You have more margin of error here than you do with the length, as your width and height measurements don’t need to be totally accurate. Even if they’re a little off, it shouldn’t affect the final calculation.
On regular slotted cartons (RSCs), the most common type of shipping box, both horizontal surfaces are identical, meaning either end could be used as the top or bottom. [4] X Research source With most packages, the height is often the smallest individual measurement.
If your box is 12 inches (30 cm) long, 4 inches (10 cm) wide, and 6 inches (15 cm) tall, doubling the width and height would give you 8 inches (20 cm) and 12 inches (30 cm), or 20 inches (51 cm) altogether. The term “girth” refers to the total distance around the thickest part of the box. [6] X Research source Don’t factor in the length measurement. The girth measurement only applies to the area encircling the shortest side of the package.
Adding 12 inches (30 cm) of length to the measurements in the previous example, you’d get a total girth of 32 inches (81 cm). If the package you’re shipping is larger than 130 inches (330 cm), you may be charged an additional special handling fee. Most shipping services won’t accept packages larger than 165 inches (420 cm). [7] X Research source
When calculating the dimensional weight of a package, it doesn’t matter which measurement corresponds to which side—all that matters is that all of your measurements are as accurate as possible. [8] X Research source Note that dimensional weight calculations can only be used with imperial units of measurement. They will not work for metric measurements. (To use the formulas below with the metric system, replace 166 with 5000. )
Some shipping services may use the term “volume” in place of “cubic size. ”
Going off the cubic size calculated in the previous example, the dimensional weight would be 2. 31 for domestic handling and 2. 76 for international shipments. [11] X Research source Don’t round your dimensional weight. It needs to be exact in order to properly tab up your shipping costs.
You can request to have your package measured at the post office if you don’t own a postage scale.
It’s important to know the actual weight of your package as well as it’s dimensional weight, as dimensional weight is only an estimate, not a precise measurement. Under ordinary circumstances, shipping costs are based on a package’s dimensional weight, which is a function of its length, width, and height. Abnormally heavy packages, however, are often priced by their actual weight to reflect the added size. [14] X Research source
