The BMW Series 1 through 7 encapsulate the different models of cars produced by the German automaker, with a higher number indicating a greater level of luxury, power, and performance. The 1 Series is a range of small family cars, while the 3 Series is a compact executive car. The 5 Series contains the line of BMW's executive cars, with the 6 Series being their line of luxury coupes. The 7 Series BMWs are the automaker's ultimate vehicles in luxury, style, and power.

Almost all of the different series have a direct competitor in the model lineups of Mercedes-Benz and Audi, BMW's fellow major German car makers and principal rivals. The 1 Series is equivalent to the Mercedes-Benz A and B Classes and Audi's A1; the 3 Series equivalent to MB's C-Class and Audi's A4; the 5 Series matched with the MB E-Class and Audi A6; The 6 Series goes head to head with Mercedes' CL and Audi's A5; and the 7 Series competes directly against the Mercedes-Benz S-Class and the Audi A8.

The most significant difference between all these models is probably the price. You obviously get what you pay for though, so some of the higher priced or higher "numbered" models may come with features that are considered superior.

Basically, the BMW 1-Series is the least expensive model and the BMW 7-Series is the most expensive. Pricing for a 128i coupe starts around $30,000, yet the V12 760Li starts at $137,000 (there are also less expensive 8 cylinder versions of the 7-Series). However, there are also multiple mid-range models including the BMW 3-Series and BMW 5-Series. There is also a top of the line BMW 6-Series coupe available.

According to the official BMW USA website, there are other model lines that may not fit perfectly into the 1-->7 numbering system such as the BMW Z4. The three SUV models, the X3, X5 and X6, appear as their own line as well.