Calculate engine displacement from bore, stroke and cylinder count.
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How do you calculate engine displacement?
Displacement = (π ÷ 4) × bore² × stroke × cylinders. With bore and stroke in mm the result is in cubic millimetres; divide by 1000 for cc, again by 1000 for litres, and by 16.387 for cubic inches. For example, a four-cylinder engine with 86 mm bore and stroke displaces about 1998 cc — a 2.0-litre engine.
Understanding your result
Displacement is the combined volume the pistons sweep in one full cycle and is a rough guide to an engine's potential power and torque. A "square" engine has equal bore and stroke; an oversquare engine (bore larger than stroke) tends to rev higher, while an undersquare one favours low-end torque.
Formula and method
Displacement = (π ÷ 4) × bore² × stroke × cylinders. With bore and stroke in mm the result is in cubic millimetres; divide by 1000 for cc, by 1000 again for litres, and by 16.387 for cubic inches.
Worked example
A four-cylinder engine with an 86 mm bore and 86 mm stroke displaces about 1998 cc — a 2.0-litre engine (roughly 121.9 cubic inches).
How to use this tool
- Enter the cylinder bore in millimetres.
- Enter the stroke in millimetres.
- Enter the number of cylinders.
- Read the displacement in cc, litres and cubic inches.
Common mistakes to avoid
- Entering bore or stroke in centimetres or inches instead of millimetres.
- Using the per-cylinder figure as the total.
- Forgetting to multiply by the number of cylinders.
About the Engine Displacement Calculator
The Engine Displacement Calculator finds the total volume swept by an engine's pistons from the bore, stroke and number of cylinders, and reports it in cc, litres and cubic inches.
Who should use this tool
Car and motorcycle enthusiasts, mechanics, engine builders and students.
Benefits
- Total and per-cylinder displacement.
- Results in cc, litres and cubic inches.
- Shows the formula and worked steps.
- Private — calculated entirely in your browser.
Practical use cases
- Working out engine size after a rebuild or bore.
- Converting between cc, litres and cubic inches.
- Comparing engine specifications.
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Frequently asked questions
How is engine displacement calculated?
It is (π ÷ 4) × bore² × stroke for one cylinder, multiplied by the number of cylinders. In millimetres, divide by 1000 to get cc.
How do I convert cc to litres?
Divide cc by 1000. So 1998 cc is about 2.0 litres.
What is a square engine?
One where the bore equals the stroke. A larger bore than stroke is oversquare; a larger stroke is undersquare.