Tare weight is the weight of a vehicle or container when it is empty. This weight is used in calculations of net weight for tasks which range from properly charging customers for consumer goods to taxing laden trucks as they cross borders. To calculate the net weight of a load, the container is weighed to establish the tare weight and then weighed again for the gross weight, and the tare is subtracted from the gross to find out how heavy the load is.

The word “tare” appears to have originated somewhere in the Middle East. The Arabic word taraha means “reject,” and the Italians apparently adopted the word for themselves as tara, for “waste.” From Italy, the word spread through France, where it evolved into tare, meaning “imperfection or wasted goods,” and then it crossed the channel to England, where it has been used since the late 1400s.

Many vehicles have marking plates with information which includes the tare weight. This is especially common with railway cars and trucks used in shipping, so that the net weight of the load can be easily calculated at any point without having to empty the vehicle to find out the tare. Such vehicles can be driven or pulled onto large and very sensitive scales for the purpose of weighing at borders and check-in stations.

In shipping, tare weight is extremely important, because it is used in the determination of the value of a load, and to calculate taxes. In many countries, truckers pay a set tax rate depending on how heavy their loads are, to ensure that trucks which contribute to the degradation of the roadway help to maintain it. Weights are also used to track loads, ensuring that no fraudulent activity occurs; this is especially important along borders, where trade tariffs may be calculated.

Many scales have a “tare weight” setting, which allows the user to place an empty container on the scale and hit the tare button to zero the scale out. In some cases, regularly used tare weights can be saved in a scale; for example, a store might want to save the setting for the glass jars it uses for olive oil, so that oil sold by weight can be quickly measured. Many cooks also use such scales for recipes which call for measures in weights, rather than volumes; incidentally, weight measures are much more reliable, which is why many baking recipes call for ingredients by weight.