Every shipping department and mailroom needs a measuring tape and a scale. The reason is that in order to calculate the correct postage or shipping charges, you have to know the DIM factor.

A DIM Factor is an acronym for Dimensional Weight Factor. It is a mathematical factor for calculating the dimensional weight of a package. UPS, FedEx, DHL, the US Post Office, and some regional carriers use dimensions as a factor in determining the cost to send a package. For example, the USPS has a DIM factor of 1 cubic foot or 12″ x 12″ x 12″. If a package exceeds a cubic foot in volume, instead of the weight of the package, they use the volume of the package to rate it.

Here are the steps for a 12 ” x 12″ x 13″ package:

- Multiply 12 x 12 x 13 = 1,872.
- Next, divide the total by 194. 1,872/194=9.65.
- Round up the result to the next whole number to get the dimensional weight of the package. 9.65 = 10 pounds.
- If the dimension exceeds the actual weight, you would use this number to calculate the shipping charges. So, in this case, even if you had a 5 pound box, (which is what happened to me) you will be charged for a 10 pound box.

For more information on how USPS calculates dimensional rate, click http://www.usps.com/prices/USPS_prices_dw_pop.html

For UPS, click http://www.ups.com/content/us/en/resources/prepare/dim_weight.html#How+To+Measure+the+Cubic+Size+of+Your+Package

For the FedEx dimensional weight calculator, click http://fedex.com/be/tools/dimweight.html

For the DHL dimensional weight calculator, click http://www.dhl-usa.com/IntlSvcs/dimweight/dimweight.asp?nav=Inttools/DimWeiCal

The USPS has a different factor than UPS and FedEx for domestic packages. You should compare rates between carriers based on package dimensions. For USPS, if the result exceeds 1,728 inches, you must use the dimensional weight. For UPS and FedEx, if the result exceeds 5,184 inches, you pay the dimensional weight.

Domestic is different than International. Here are the current factors:

- Domestic you divide by 194
- International you divide by 166