The model year (MY) is a method of describing the version of a product which has been produced over multiple years. The model year is sometimes the same as the calendar year in which the product was manufactured, however the model year can be up to two years different from the actual year.
A common usage of model years is for automobiles in the United States and Canada. In other countries, automobiles are more often described by their generation instead of model year.
The practice of identifying revisions of automobiles by their model year is strongest in Canada and the United States. The letters "MY" precedes the year (eg MY2019) indicates that it is the model year, however even without this prefix it is usually the model year (instead of the calendar year) that is being referred to.
The new model year typically begin with the fourth quarter of the preceding year. This was partly due to the advertising of a new model being coordinated with the launch of the new television season in late September, because of the heavy dependence between television to offer products from automakers to advertise, and the car companies to launch their new models at a high-profile time of year. Imported cars in the U.S. and Canada from other countries typically adopt the model year convention in the U.S. and Canada, even when this system is not used for the same cars when sold in other countries.
The concept of yearly styling updates (a practice adopted from the fashion industry) was introduced to General Motors' range of cars by Alfred P. Sloan in the 1920s. This was an early form of planned obsolescence in the car industry, where yearly styling changes meant consumers could easily discern a car's newness, or lack of it. Other major changes to the model range usually coincided with the launch of the new model year. The practice of beginning production of next year's model before the end of the year is also a long standing tradition in America, for example the 1928 model year of the Ford Model A began production in October 1927 and the 1955 model year of the Ford Thunderbird began production in September 1954.
For regulation purposes (such as VIN numbering and EPA emissions certification), government authorities allow cars of a given model year to be sold starting on January 1 of the previous calendar year. For example, this means that a 2019 model year vehicle can legally go on sale on January 1, 2018. This has resulted in a few cars in the following model year being introduced in advertisements during the NFL Super Bowl in February. A notable example of an "early" model year launch would be the Ford Mustang, introduced as an early 1965 model (informally referred to as "1964½") in April 1964 at the World's Fair, several months before the usual start of the 1965 model year in August 1964.
In other countries, it is more common to describe the age of a car by its generation instead of the specific year, using terms such as "third generation", "Mark III" or the manufacturer's code for that generation (such as "BL" being the code for a Mazda 3 built between November 2008 and June 2013).
In Europe, the lesser use of model years as a descriptor is partly because since the 1980s many vehicles are introduced at the Geneva Motor Show in March, the Frankfurt Motor Show in September or the Paris Motor Show in September. New models have increasingly been launched in June or July.
The Vehicle Identification Number (VIN) scheme, mandatory serial number for each vehicle which is used in many countries, includes the model year of the vehicle as the 10th digit. The actual date that the vehicle was produced is not part of the VIN, however it is often shown on the manufacturer's build plate.
In addition to automobiles, some other products that often have model years include: