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Engine Bore, Stroke & Swept Volume

Find total swept displacement from a common cylinder bore, stroke and positive whole-cylinder count.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

Four cylinders with a 10 cm bore and a 10 cm stroke have total swept volume 1,000π cm³, approximately 3,141.593 cc or 3.142 liters.

Total swept volume = cylinder count × π × bore² × stroke / 4

Worked example

Enter these known values and leave the other values blank.

Number of identical cylinders
4
Cylinder bore diameter
10 cm
Full piston stroke
10 cm
Total swept displacement
3141.6 cc

Assumptions and limitations

  • Count is a positive whole number. Bore, stroke and total displacement are positive. All cylinders are assumed to share the same bore and stroke.
  • Swept volume is the volume displaced during one full stroke per cylinder, summed over cylinders. It excludes clearance volume at top dead center.
  • Displacement alone does not determine power, torque, compression ratio or fuel use. The result is geometric and does not depend on two-stroke versus four-stroke timing.

Common questions

Do I use the bore radius or diameter?

Enter diameter. The formula divides its square by four to obtain radius squared.

Does a four-stroke engine need an extra factor of four?

No. Stroke count in the engine cycle does not multiply the geometric swept displacement.

References

Bookify requires the positive cylinder count to be a whole number. Bookify replaces the captured rounded US gallon with the exact 3.785411784-liter definition.

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