CWT is the abbreviation for hundredweight. During the nineteenth century, hundredweight became popular as a standardized measurement to simplify business functions like setting freight rates. The hundredweight is rarely used today. However, it is still useful to know how to calculate hundredweight, because the CWT standard is still accepted in agriculture and for some freight charges.

The CWT Standard

The hundredweight was once widely used as a standardized measure for agricultural commodities like grain and livestock. It is still in use, although its popularity has declined. For example, rough rice on the Chicago Mercantile Exchange may still be listed as 2,000 CWT per futures contract according to Investopedia. Some freight shipping firms still list rates in hundredweight as well.

There are actually two hundredweight standards. In North America, hundredweight is based on the short ton, which is equal to 2,000 pounds. A hundredweight equals 5 percent of a ton, or 100 pounds. However, in the United Kingdom the Imperial long ton is used. ConvertUnits.com says a long ton equals 2,240 pounds, so one hundredweight equals 112 pounds.

Calculating CWT

To find the weight of a commodity or freight shipment, first determine its total weight in pounds. Cavalier instructs you to divide this total by 100 to express the quantity in hundredweight. Suppose you have 1,680 pounds of rice on hand. Dividing 1,680 by 100 gives you 16.8 CWT. Calculate the long or British hundredweight the same way, substituting 112 pounds. Using this Imperial measure, you get 1,680 pounds divided by 112. The total works out to 15 long CWT.

Determining CWT Freight Charges

You may occasionally need to determine freight charges using rate tables expressed in hundredweight. Find the total weight of the shipment, including pallets or skids. For instance, if a shipment weighs 1,600 pounds plus pallets weighing 80 pounds, the shipping weight equals 1,680 pounds.

Then, determine the billable weight. Billable weight applies on shipments that measure larger than the standard 48 inches in length, width and height. When this is the case, you must use a formula provided by the shipper to calculate a theoretical volume-based weight.

If this volume-based weight is greater than the actual weight, you must use it to calculate the freight charges. For example, if the shipper's formula produces a volume-based figure of 1,800 pounds and the actual weight is 1,680 pounds, use 1,800 pounds. Once you know the billable weight, convert to CWT by dividing by 100. For a billable weight of 1,680 pounds, you get 16.8 CWT. Multiply CWT by the applicable rate. If the rate is $9 per CWT, multiply $9.00 by 16.8 for a freight charge of $151.20.

Converting Short CWT to Long CWT

When you want to change short CWT to the long CWT measure used in the UK, use a two-stem process. First, multiply short CWT by 100 to state the weight in pounds. Divide by 112 to express the weight in long or Imperial hundredweight. For example, 16.8 short CWT equals 1,680 pounds. Dividing by 112 gives a result of 15 long CWT.