Engine Displacement

Free Engine Displacement calculator with clear step-by-step results.

About Engine Displacement

Displacement is the swept volume of one cylinder multiplied by cylinder count, where swept volume is the bore's circular area times the stroke. The bore-to-stroke ratio is the other number worth knowing: above 1.0 is oversquare and revs freely, below 1.0 is undersquare and favours low-end torque.

Formulas

Swept volume per cylinder

cc = pi x (bore mm / 20)^2 x (stroke mm / 10)

Total displacement

Total cc = swept volume per cylinder x number of cylinders

Worked example

With the default values below, Engine Displacement returns Total displacement of 1,998.2. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cylinder boreaccepts 10–250 mm: 86 mm
Piston strokeaccepts 10–300 mm: 86 mm
Number of cylindersaccepts 1–16: 4
Compression ratioaccepts 4–25 :1: 10.5 :1

Results

Total displacement: 1,998.2 cc
Displacement in litres: 1.998 L
Swept volume per cylinder: 499.56 cc
Bore to stroke ratio: 1.000

Step by step

1Values used
2Swept volume per cylinder
3Total displacement
4Total displacement= 1,998.2 cc
5Displacement in litres= 1.998 L
6Swept volume per cylinder= 499.56 cc
7Bore to stroke ratio= 1.000

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why divide bore by 20?

It converts millimetres to centimetres and halves the bore to get the radius in one step, so the result comes out directly in cubic centimetres.

Does displacement determine power?

It sets the air the engine can breathe per cycle, but boost, compression, valve timing and rev limit matter just as much. A 2.0 litre turbo routinely outproduces a 3.0 litre naturally aspirated engine.