Engine displacement

The overall displacement for a typical reciprocating piston engine is calculated by multiplying together three values; the distance travelled by the piston (the stroke length), the circular area of the cylinder, and the number of cylinders in the whole engine.

Manufacturers and regulators may develop and use specialised formulae to determine a comparative nominal displacement for variant engine types.

In several countries fees and taxes levied on road vehicles by transport authorities are scaled in proportion to engine displacement.

This was especially common in US muscle cars, like the Ford Mustang Boss 302 and 429, and later GT 5.0L, The Plymouth Roadrunner 383, and the Chevrolet Chevelle SS 396 and 454.

However, trends towards downsizing and hybrid/electric drivetrains since 2010 have resulted in far fewer model names being based on the engine displacement.