Supercar is a term used for a high end sports car, typically an exotic or rare one, whose performance is highly superior to that of its contemporaries. The proper application of the term is subjective and disputed, especially among enthusiasts. The use of the term is dependent on the era: a vehicle that is considered to be a supercar at one time may not retain its superiority in the future. The automotive press frequently calls new exotic cars "supercars".
 Origin of the term
 Performance criteria
The term supercar usually refers to factory-built, street-legal sports cars, rather than modified production cars that may have similar performance. Supercars are usually designed for road and amateur track use rather than racing alone, and because of this their standard equipment often does not include roll cages and other features required for race cars.
Some common criteria for measuring whether a car should be considered a supercar include the following:
Many supercars have a rear mid-engine (RMR), rear-wheel drive layout, which allows for better distribution of weight. This potentially increases overall traction, or grip, by moving weight away from the front and back ends of the car. The result is often handling, acceleration and braking capabilities that may have otherwise have been impossible to attain. Some supercar makers have started building all-wheel-drive supercars as new engines are producing more power than two wheels can take advantage of. For an example, see Bugatti Veyron or Lamborghini Murcielago.
 Power-to-weight ratio
Most supercars have high engine power and low vehicle mass, for the sake of high acceleration (see Newton's Second Law) and good handling dynamics. For example, the 2004 Porsche Carrera GT masses just 3 kilogram per kilowatt (5 lb/hp)—compare this to the similarly sized and shaped Porsche Boxster with nearly 7.1 kg/kW (11.7 lb/hp). The McLaren F1, introduced in 1991 and one of the fastest supercars of the 20th century, produced 467.6 kW (627.1 hp) against a mass of 1140 kg (2513 lb), translating to 2.44 kg/kW (4.01 lb/hp). Certain vehicles have a high power-to-weight ratio despite their heavy weight, due to a very powerful engine. For example, the Bugatti Veyron carries 2.61 kg/kW (4.30 lb/hp) despite weighing 1950 kg (4299 lb), including fuel, due to its 746 kW (1001 hp) engine. The Koenigsegg CCR and Koenigsegg CCX have the highest power-to-weight ratio among production supercars: with 601 kW (806 hp) (on California grade 91 octane gasoline) and a weight of just 1,180 kg (2,601 lb) the Koenigsegg carries only 1.96 kg/kW (3.23 lb/hp). According to the Shelby Super Cars website, the Ultimate Aero TT holds the new production record, carrying a mere 1.42 kg/kW (2.33 lb/hp).
Supercars, by the usual definition, offer extremely high acceleration compared to most vehicles, including ordinary sports cars. Some current expectations are as follows:
- 0 to 100 km/h (62 mph): Under 4 seconds for virtually all supercars today. The Ultima GTR can go from 0 to 100 km/h in 2.6 seconds and the Bugatti Veyron can do this in 2.5 seconds.
- 0 to 160 km/h (100 mph): Under 6 seconds is generally recognized as the standard, with undisputed supercars being significantly faster.
- The Ultima GTR, introduced in 2006, has recorded a 0 to 160 km/h time of 5.3 seconds.
- A Bugatti Veyron can achieve 0 to 160 km/h in 5.5 seconds.
- 0 to 320 km/h (200 mph): Under 30 seconds. McLaren F1 28 seconds, Saleen S7 23 seconds, Bugatti Veyron 22 seconds.
- Standing quarter-mile (400 meter): Under 13 seconds is arguably a requirement, as is a trap or terminal speed of at least 175 km/h (110 mph).
- The Ferrari Enzo completes the quarter mile from a stop in about 11.1 seconds at 214 km/h (133 mph).
- The Koenigsegg CCR, introduced in 2004, is officially claimed to run the quarter mile in "9 seconds, end speed 235 km/h (146 mph)"
- Standing mile (1.6 km): Trap (terminal) speed of at least 320 km/h, for example the Saleen S7, Bugatti Veyron, Pagani Zonda, Koenigsegg CCR, McLaren F1, Ferrari FXX.
 Top speed
- On March 31, 1998, the McLaren F1 LM prototype set the speed record at 400km/h (250mph) at 7800 rpm. The production models are normally limited to giving them a top speed around 231 mph. The prototype was driven by Andy Wallace on the 9 km straight at Volkswagen's Ehra-Lessien test track in Wolfsburg, Germany.
- On February 28, 2005, the Koenigsegg CCR with 601 kW (806hp) achieved a top speed of 387.87 km/h (241.01 mph) on default settings. The car was driven on Italy's Nardo Prototipo proving ground, a circular track with a circumference of 12.5km. This exceeded the McLaren's record  The steering wheel was kept at 30 degrees, slowing the car; the car has not been tested on a straight track.
- In October, 2005, Car and Driver magazine's editor Csaba Csere test drove the final production version of the Veyron for the November 2005 issue. This test, at Volkswagen's Ehra-Lessien test track, reached a top speed of 407 km/h (253 mph). The Veyron can also go from 0 to 300 km/h (190 mph) in just under 19 seconds .
A supercar is usually built for maximum cornering and road gripping ability in order to achieve superior cornering speeds. Lateral g-forces during the tightest turns can generally exceed 1 g.
A popular benchmark is a lap time around the Nürburgring of under 8 minutes. There are also other tracks where supercars are being tested. Lap time tables from different racetracks are posted at fastestlaps.com.
 Other criteria
In addition to performance, the following criteria are also cited in determining if a particular sports car or exotic car deserves the supercar moniker:
- Brand: Supercars are often very brand-centric (e.g. Ferrari) and a new brand wanting to join the list has to prove itself before its acceptance.
- Styling: Supercars often feature groundbreaking styling elements. The Formula One-inspired Enzo Ferrari, for example, set a new styling direction for that company.
- Rarity: Virtually all cars classified as supercars undergo a very limited production run, typically no more than a few thousand in total. For example, the Corvette Z06, though an extremely fast car, is mass produced and is very common, and thus is not sufficiently rare to be considered a supercar.
- Focused design: Supercars are not designed to be practical transportation devices, with functionality varying widely between different examples. Many car body styles (including 2+2 coupe, station wagon, and pickup truck) make inherent tradeoffs of performance potential for utility. By this measure, extreme vehicles like the Dodge Ram SRT 10 are not normally called supercars (in the case of Dodge Ram SRT-10, it is classified as a truck, not car, so the car-based description would not fit anyway). While one undisputed supercar, the McLaren F1, featured seating for three (and had a number of useful storage spaces), performance was not sacrificed, but instead improved by the seating design: the driver's central position lowered the vehicle's polar moment of inertia and increased its turning ability.
 Historic supercars
Examples of cars that are generally agreed to have been supercars in their time.
- Aston Martin DB4 GT Zagato
- Bugatti Veyron
- Bugatti EB110
- Ferrari Enzo
- Ferrari 250 GTO
- Ferrari 288 GTO
- Ferrari F40
- Ferrari F50
- Ferrari 599 GTB Fiorano
- Jaguar XKSS
- Jaguar XJ220
- Koenigsegg CCX
- Koenigsegg CCR
- Koenigsegg CC8S
- Lamborghini Countach
- Lamborghini Miura
- Lamborghini Diablo
- Lamborghini Murciélago
- Lamborghini Murciélago LP640
- Maserati MC12
- Mercedes-Benz SLR McLaren
- Mercedes-Benz 300SL 'Gullwing'
- McLaren F1
- Pagani Zonda
- Porsche 959
- Porsche Carrera GT
- Saleen S7
- Vector W8