Engine Displacement Calculator
This engine displacement calculator turns bore, stroke and number of cylinders into total displacement in cc, litres and cubic inches, for cars, motorcycles and scooters.
Example: Bore (cylinder diameter) 86 mm · Stroke 86 mm · Number of cylinders 4 cyl. · Engine speed (optional) 6,000 rpm → Displacement: 1,998 cc (2 litres). Source: Wikipedia – Hubraum (V = π/4 · d² · s · Zylinderzahl). Updated: .
How it is calculated
A four-cylinder with an 86 mm bore and 86 mm stroke displaces 1,998 cc, about 2.0 litres. Displacement is the volume all pistons together sweep on their way between the dead centres.
How it is calculated
Each cylinder is a circular cylinder with the bore as its diameter and the stroke as its height: V = π/4 · bore² · stroke. The calculator converts millimetres to cubic centimetres and multiplies by the number of cylinders. You also get the value in cubic inches (1 in³ = 16.387064 cm³), the bore-to-stroke ratio and, if you give an engine speed, the mean piston speed.
Good to know
- If the bore is larger than the stroke the engine is oversquare; such engines usually rev higher.
- Two-strokes and rotary engines have their own rules for stating displacement; the calculator applies to reciprocating engines.
- After boring out or fitting a different crank, the volume changes; enter the new dimensions to recalculate.
Frequently asked questions
How do you calculate engine displacement?
Per cylinder with V = π/4 · bore² · stroke; in mm³ divided by 1000 this gives cc. Multiply by the number of cylinders for the total.
How do you convert cc to litres?
Divide by 1000: 1,998 cc is 1.998 litres. The calculator shows both.
What are oversquare and undersquare engines?
Oversquare means the bore is larger than the stroke, undersquare the opposite. It affects how well the engine revs and its torque curve.
How do I convert cubic inches to litres?
Multiply cubic inches by 16.387064 to get cc, then divide by 1000. A 350 cubic inch engine is about 5.7 litres.
Sources and legal basis
- Wikipedia – Hubraum (V = π/4 · d² · s · Zylinderzahl)
- Wikipedia – Engine displacement (Bohrung, Hub, Hubraum)
- Wikipedia – Cubic inch (1 in³ = 16,387064 cm³)
As of: · Editorial policy
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