Performance & Engine

Engine Calculator

Compute bore, stroke, displacement, and related specs.

How to Calculate CID

Bore Diameter (in)*

Number of Cylinders*

Stroke (in)*

Cubic Inch Displacement Result

Formula: CID = Bore² × 0.7854 × Stroke × Cylinders

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About this tool

The BuildLockr engine calculator helps builders design custom powerplants. Use this tool to instantly calculate your engine's Cubic Inch Displacement (CID) based on the bore size, stroke length, and number of cylinders. Whether you are building a stroked LS engine or machining a vintage flathead, this engine displacement calculator ensures perfectly accurate specs. This helps engine builders plan precise overbore sizes and select the correct rotating assemblies.

Common Displacements

Classic V8 Examples (Bore x Stroke)

• Chevy 302: 4.00" x 3.00" (301.6 CID)
• Chevy 350: 4.00" x 3.48" (349.8 CID)
• Ford 302: 4.00" x 3.00" (301.6 CID)
• LS1 (5.7L): 3.898" x 3.622" (345.8 CID)
• LS3 (6.2L): 4.065" x 3.622" (376.0 CID)
• Chevy 454: 4.25" x 4.00" (453.9 CID)

Understanding CID

Cubic Inch Displacement (CID) measures the total swept volume of all the pistons in an engine. A larger displacement allows an engine to pull in more air and fuel, typically resulting in higher power and torque.

Bore vs Stroke

• Oversquare: Bore > Stroke (Rev higher, more HP)
• Undersquare: Stroke > Bore (More low-end torque)
• Square: Bore = Stroke (Balanced characteristics)

Common Engine Size Questions

What is Cubic Inch Displacement (CID)?

Cubic Inch Displacement (CID) is the total volume of air that all of the engine's cylinders sweep through in a single engine cycle. A larger CID means the engine can burn more fuel and air, generally creating more power.

How do you calculate engine displacement?

Engine displacement is calculated by finding the volume of a single cylinder and multiplying it by the total number of cylinders. The formula is: CID = Bore² × 0.7854 × Stroke × Cylinders.

What does "bored and stroked" mean?

When an engine is "bored," the diameter of the cylinders is machined wider to fit larger pistons. When an engine is "stroked," a new crankshaft is installed that pulls the pistons further down into the cylinder. Both methods increase the total displacement of the engine.