# Cubic Inch Displacement

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

Cubic inch displacement, abbreviated as CIOD, is the size of the engine.  Determine by calculating the engine number of cylinders multiplied cylinder bore area multiplied by the stroke of the crankshaft.

## Cubic Inch Displacement formula

 $$\large{ CID = NOC \; 0.7854 \; BORE^2 \; STROKE }$$

### Where:

 Units English Metric $$\large{ CID }$$ = cubic inch displacement $$\large{in^3}$$ $$\large{mm^3}$$ $$\large{ BORE }$$ = cylinder bore size $$\large{in}$$ $$\large{mm}$$ $$\large{ NOC }$$ = number of cylinders - - $$\large{ STROKE }$$ = piston stroke length $$\large{in}$$ $$\large{mm}$$