Free Tool
Engine Displacement Calculator
Enter bore, stroke, and cylinder count to get engine displacement in cubic inches (CID), liters, and cubic centimeters (cc) instantly.
Displacement Formula
CID = 0.7854 × bore² × stroke × cylCubic inches (0.7854 = π ÷ 4)Liters = CID × 0.0163871Convert cubic inches to literscc = CID × 16.387Convert cubic inches to cubic centimetersHow Engine Displacement Is Calculated
Engine displacement is the total volume swept by all of the pistons as they move through one full stroke. It is calculated from three numbers: the bore (cylinder diameter), the stroke (how far each piston travels), and the number of cylinders. The formula treats each cylinder as a cylinder-shaped volume — area of the bore circle (0.7854 × bore², where 0.7854 is π ÷ 4) multiplied by the stroke — then multiplies by the cylinder count to get total displacement.
With bore and stroke measured in inches, the result comes out in cubic inches of displacement, or CID. A classic 4.00 in bore by 3.48 in stroke V8 works out to roughly 350 CID. Because engine specs are quoted in both imperial and metric units, this tool also converts CID to liters (multiply by 0.0163871) and to cubic centimeters (multiply by 16.387), so that same 350 CID engine reads as about 5.7 L or 5,735 cc — the kind of figure you see stamped on a valve cover or listed in a service manual.
Displacement is one of the most common calculations on the ASE A1 Engine Repair exam. Technicians use it to identify an engine, verify a rebuild's specifications, and reason about performance and emissions. Note that displacement is separate from compression ratio: displacement is the swept volume only and does not include the combustion-chamber clearance volume that a compression-ratio calculation requires.
Frequently Asked Questions
How do you calculate engine displacement?
Multiply 0.7854 (which is π ÷ 4) by the bore squared, then by the stroke, then by the number of cylinders. Bore and stroke are in inches, and the result is displacement in cubic inches (CID). For example, a 4.00 in bore, 3.48 in stroke, 8-cylinder engine works out to about 350 CID.
How do I convert cubic inches to liters?
Multiply cubic inches by 0.0163871 to get liters. A 350 CID engine is about 5.7 liters. To go from liters to cubic inches, divide by 0.0163871 (or multiply by roughly 61.02). One cubic inch equals 16.387 cubic centimeters (cc), so a 350 CID engine is about 5,735 cc.
What is the difference between bore and stroke?
Bore is the diameter of each cylinder, and stroke is the distance the piston travels from bottom dead center to top dead center. Together with the number of cylinders they determine total displacement. An engine with a bore larger than its stroke is 'oversquare,' and one with a longer stroke than bore is 'undersquare.'
Why does displacement matter on the ASE exam?
Displacement is a fundamental engine-specification calculation on ASE tests, especially the A1 Engine Repair area. Technicians need to interpret bore and stroke specs, convert between CID and liters when reading service data, and understand how displacement relates to engine performance and emissions.
Does this calculator account for compression ratio?
No. Displacement is the swept volume of all the cylinders and does not include the combustion-chamber (clearance) volume. Compression ratio is a separate calculation that compares total cylinder volume at bottom dead center to the volume at top dead center, so it requires the combustion-chamber volume as an additional input.
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