Engine displacement calculator

Displacement is the volume swept by all the pistons. Enter the bore, stroke and number of cylinders. Optionally enter a new bore to see the effect of a big bore kit or overbore.

Result

Displacement	cm³ ( l, cu in)
Per cylinder	cm³
Bore/stroke ratio	–
New displacement	cm³
Displacement change	%

Results are calculated estimates. Always check your vehicle manufacturer's instructions.

Matching products: Cylinders Pistons

How to use

Find the bore and stroke in the service manual or specifications (e.g. 54 × 54.5 mm).
Enter the number of cylinders.
For a big bore kit or overbore, enter the new bore (e.g. 56 mm or 54.5 mm).

Frequently asked questions

How is displacement calculated?

Displacement = π/4 × bore² × stroke × number of cylinders. The result in millimetres is divided by 1000 to get cubic centimetres (cm³ or cc).

What are oversquare and undersquare engines?

If the bore is larger than the stroke, the engine is oversquare (short-stroke) and likes to rev high. If the stroke is longer, it is undersquare (long-stroke) and gives more low-rpm torque.

Does a big bore kit affect registration?

Increasing displacement changes the vehicle's technical data. Depending on the change and the licence category it may require re-registration – check with your national vehicle authority.

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