Engine Displacement Calculator
Work out an engine's displacement from its bore, stroke, and cylinder count. Enter bore and stroke in millimeters or inches to get the total swept volume in cc, liters, and cubic inches.
Example: with Bore 86 · Stroke 86 · Bore/stroke unit millimeters (mm) · Number of cylinders 4 → Displacement: 1,998 cc (2.0 L).
- In cubic inches121.9 ci
- Per cylinder499.6 cc per cylinder
Computed by the calculator below using its default values. Change any input to see your own numbers.
Displacement = π/4 × bore² × stroke × cylinders. It is the total volume the pistons sweep — the headline number behind a badge like 2.0L or 350.
What displacement actually measures
Displacement is the total volume swept by every piston in one full stroke. For one cylinder it is the area of the bore (a circle, π/4 × bore²) multiplied by how far the piston travels (the stroke). Multiply by the number of cylinders and you have the engine's size — the number carmakers round into a badge like 2.0L or a 350.
Bigger displacement means each intake stroke can pull in more air and fuel, which is why it tracks loosely with torque and power. But it is only geometry: it says nothing about how well the engine breathes, its compression, or whether it is turbocharged.
Bore, stroke, and the same size two ways
Two engines can share a displacement yet feel completely different. A wide bore with a short stroke lets valves grow and revs climb, favoring peak power. A narrow bore with a long stroke builds low-end torque and limits RPM. Enter both numbers and you will see how they trade off inside the same total volume.
Because the answer comes straight from the dimensions, use accurate figures. A tenth of a millimeter of bore, squared across eight cylinders, moves the result more than you would expect.
How it’s calculated
Displacement V = (π/4) × bore² × stroke × number of cylinders. Bore and stroke are converted to millimeters (1 in = 25.4 mm exactly), giving cubic millimeters; dividing by 1,000 gives cubic centimeters (cc), and by 1,000,000 gives liters. Cubic inches use 1 ci = 16.387064 cc.
Pure swept-volume geometry. It excludes combustion-chamber (clearance) volume, so it is displacement, not the volume used to figure compression ratio.
Displacement of some well-known engines
| Engine | Bore × stroke (mm) | Cyl | Displacement | Cubic inches |
|---|---|---|---|---|
| 2.0 L inline-4 | 86.0 × 86.0 | 4 | 1,998 cc | 122 ci |
| Chevy 350 V8 | 101.6 × 88.4 | 8 | 5,733 cc | 350 ci |
| Honda B16 inline-4 | 81.0 × 77.4 | 4 | 1,595 cc | 97 ci |
| Harley 883 V-twin | 76.2 × 96.8 | 2 | 883 cc | 54 ci |
Computed with V = π/4 × bore² × stroke × cylinders from published bore/stroke specs; rounded.
Common mistakes
- Mixing units — entering bore in inches but stroke in millimeters throws the volume off by orders of magnitude.
- Using the bore radius instead of the diameter; the formula wants the full bore, then squares it.
- Forgetting to multiply by the cylinder count, which gives per-cylinder volume instead of total.
- Confusing displacement with the volume used for compression ratio, which also includes the combustion chamber.
Frequently asked questions
What is the engine displacement formula?
Displacement = π/4 × bore² × stroke × number of cylinders. Bore and stroke are the piston diameter and travel; the result is the total volume the pistons sweep, usually shown in cc, liters, or cubic inches.
How do I convert cc to cubic inches?
Divide cubic centimeters by 16.387064. So a 5,733 cc engine is about 350 cubic inches, the classic small-block figure.
Does bigger displacement always mean more power?
Not directly. More displacement moves more air per stroke, which helps, but tuning, compression, RPM, and forced induction matter just as much — a small turbo engine can beat a larger naturally aspirated one.
Why do two engines with the same size feel different?
Bore and stroke can be traded within the same displacement. A short-stroke, big-bore engine revs high for peak power; a long-stroke engine makes torque down low.
Is displacement the same as engine capacity?
Yes. Capacity, displacement, and swept volume all name the same number — the total volume swept by the pistons.