Engine Displacement Calculator

Calculate engine displacement from your physical measurements using the standard formula with consistent SI units.

Quick Facts

Displacement formula
V = (π/4) × B² × S × N
B = bore (cylinder diameter), S = stroke (piston travel), N = number of cylinders.
Unit conversions
1 L = 1000 cm³ = 61.024 in³
Displacement is commonly quoted in liters (L), cubic centimeters (cc), or cubic inches (ci).
Typical passenger car
1.0 L – 3.5 L
Most modern passenger-car engines fall in this displacement range; trucks and performance engines run larger.

Your Results

Calculated
Total Displacement
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V = (π/4) × B² × S × N, in liters
Displacement (cc)
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Total swept volume in cubic centimeters
Displacement (in³)
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Total swept volume in cubic inches
Per-Cylinder Volume
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Swept volume of a single cylinder, in cc

Ready

Enter bore, stroke, and cylinder count, then press Calculate.

Formula and Method for Engine Displacement

Engine displacement is the total volume swept by all the pistons as they travel from bottom dead center to top dead center inside their cylinders. Each cylinder is treated as a cylinder-shaped volume: its cross-sectional area is a circle set by the bore (the cylinder's internal diameter), and its height is the stroke (the distance the piston travels). Multiplying that swept volume by the number of cylinders gives the engine's total displacement: V = (π/4) × B² × S × N, where B is bore, S is stroke, and N is the number of cylinders.

How the calculation works

Enter the bore and stroke in the same unit (millimeters or inches) and the number of cylinders. The calculator first finds the swept volume of a single cylinder using the circle-area formula (π/4) × B², multiplied by the stroke length, then multiplies that per-cylinder volume by the number of cylinders to get total displacement. The result converts automatically: cubic centimeters (cc) come directly from bore and stroke in centimeters, liters are cc ÷ 1000, and cubic inches use the conversion 1 in³ = 16.387064 cm³.

Common mistakes

  • Mixing units: bore and stroke must be in the same unit before squaring and multiplying — entering one in millimeters and the other in inches will give a meaningless result.
  • Using radius instead of bore: bore is the full cylinder diameter, not the radius. Using a radius value in place of bore roughly quadruples the calculated displacement.
  • Forgetting cylinder count: per-cylinder swept volume is only part of the picture — total displacement scales directly with the number of cylinders (4, 6, 8, and so on).

Real-world applications

  • Vehicle specification sheets and marketing names (e.g., "2.0L", "5.7L V8") are rounded versions of the displacement computed from bore, stroke, and cylinder count.
  • Displacement correlates with an engine's naturally aspirated torque and power potential, which is why it factors into insurance classes, vehicle taxes, and racing class rules in many countries.
  • Engine builders use the bore/stroke relationship to classify an engine as "oversquare" (bore > stroke, favors high RPM) or "undersquare" (stroke > bore, favors low-RPM torque).
  • Machinists recalculate displacement after an engine rebuild when the bore is enlarged ("overbored") to remove cylinder wall damage, since a larger bore slightly increases total displacement.

Frequently Asked Questions

What is the formula for engine displacement?
Total engine displacement equals the swept volume of one cylinder multiplied by the number of cylinders: V = (π/4) × B² × S × N, where B is the cylinder bore (diameter), S is the piston stroke length, and N is the number of cylinders. A 4-cylinder engine with an 86 mm bore and 86 mm stroke displaces about 1,998 cc, or roughly 2.0 liters.
Where do I find my engine's bore and stroke?
Bore and stroke are published in the manufacturer's engine specifications, service manual, or an engine-code lookup for your vehicle. You can also measure bore directly with a cylinder bore gauge or caliper, though getting stroke usually requires partial disassembly to measure crankshaft throw.
Why is displacement rounded to a figure like "2.0L" in marketing?
Automakers round the calculated displacement to the nearest common marketing figure. An engine that computes to 1,998 cc from its actual bore, stroke, and cylinder count is sold as a "2.0L" even though the precise swept volume is a few cc away from an even 2,000 cc.
Does more displacement always mean more horsepower?
Larger displacement lets more air and fuel burn per cycle, which raises the potential for power, but actual output also depends on volumetric efficiency, compression ratio, forced induction such as turbocharging, and RPM range — two engines with identical displacement can produce very different horsepower.

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