What engine displacement is
Engine displacement is the total volume swept by all pistons inside an engine’s cylinders during one complete stroke — a standard way to describe engine size.
The formula
Each cylinder’s swept volume is V = πr² × stroke, where r is half the bore (cylinder diameter). Total displacement is this volume multiplied by the number of cylinders. Results are commonly expressed in cubic centimeters (cc), liters, or cubic inches.
This is the standard geometric displacement formula used throughout automotive and mechanical engineering references.
Last reviewed August 2026