About

Engine displacement defines the total volume of air pushed by the pistons within the cylinders during a single movement from bottom dead center to top dead center. This volume dictates the potential power output and fuel consumption characteristics of an internal combustion engine. Mechanics and engine builders use this data to determine compression ratios, select appropriate camshaft profiles, and verify class compliance for racing regulations.

Precision is required when calculating displacement after machine work. Overboring cylinders by even 0.030 inches significantly changes the total swept volume. This tool handles mixed unit inputs, allowing users to input bore in inches and stroke in millimeters, or vice versa, normalizing all data to provide accurate results in cubic centimeters (cc), liters (L), and cubic inches (CID).

Formulas

The displacement volume (V) is calculated using the cylinder geometry. The formula represents the volume of a cylinder multiplied by the total number of cylinders.

V = π4 × B² × S × N

Where:

B = Cylinder Bore (diameter)
S = Piston Stroke (travel distance)
N = Number of Cylinders

For conversion between metric and imperial volume units, the following constants are used:

1 CID ≈ 16.387 cc

1 L = 1000 cc

Reference Data

Engine Platform	Bore (mm)	Stroke (mm)	Cylinders	Displacement (cc / CID)
Chevy Small Block 350	101.6	88.4	8	5733 / 350
Ford Windsor 302 (5.0)	101.6	76.2	8	4942 / 302
Honda B16A	81.0	77.4	4	1595 / 97
Nissan RB26DETT	86.0	73.7	6	2568 / 156
Toyota 2JZ-GTE	86.0	86.0	6	2997 / 183
Chrysler 426 Hemi	107.95	95.25	8	6974 / 426
Porsche 911 (991 GT3)	102.0	81.5	6	3996 / 244
BMW S54B32	87.0	91.0	6	3246 / 198
Ferrari F136 F (458)	94.0	81.0	8	4497 / 274
Dodge Viper V10 (Gen 5)	103.0	100.6	10	8382 / 511
Subaru EJ257	99.5	79.0	4	2457 / 150
GM LS7 (Z06)	104.8	101.6	8	7011 / 428

Frequently Asked Questions

This refers to the Bore/Stroke ratio. An Oversquare engine (Bore > Stroke) typically revs higher due to lower piston speed but may have less low-end torque. An Undersquare engine (Stroke > Bore) generally produces more torque at lower RPMs but is limited in maximum piston speed. A Square engine has equal dimensions.

Increasing the bore diameter exponentially increases volume because the bore value is squared in the formula. A small increase, such as 0.030 inches (0.762 mm), can add significant displacement across 8 cylinders, often requiring carburetor rejetting or ECU remapping.

Manufacturers often round numbers for marketing. For example, the Ford "5.0" is technically 4942cc (4.9L), but 5.0L sounded better. Conversely, the Chevy 305 is usually cited as 5.0L as well, despite being slightly larger than the Ford. Always calculate exact displacement for compression ratio math.

No. Head gasket thickness affects the combustion chamber volume and compression ratio, but it does not alter the swept displacement. Displacement is strictly defined by the bore area and the piston stroke length.