Enter bore, stroke, and cylinder count, then calculate to see results here.
| Parameter | Value | Notes |
|---|---|---|
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Typical production engines and their approximate bore, stroke, and displacement values.
| Engine type | Bore (mm) | Stroke (mm) | Cylinders | Approx. displacement (L) |
|---|---|---|---|---|
| Inline-4 2.0L | 86 | 86 | 4 | 2.0 |
| V6 3.5L | 94 | 90 | 6 | 3.5 |
| V8 5.0L | 92 | 92 | 8 | 5.0 |
| Motorcycle twin 0.7L | 80 | 68 | 2 | 0.7 |
The swept volume for a single cylinder is computed from its bore and stroke. The bore defines the cylinder diameter, and the stroke defines the piston travel distance.
First, the bore is converted to a radius. The cylinder is treated as a geometric cylinder. The swept volume per cylinder is:
Vcyl = π × (bore / 2)2 × stroke
When bore and stroke are expressed in centimeters, the result is in cubic centimeters (cc). Total engine displacement is then:
Vtotal = Vcyl × number of cylinders
Cubic centimeters are converted to liters by dividing by 1000, and to cubic inches using the factor 1 cu in = 16.387064 cc.
- Enter the bore per cylinder and choose its unit (mm, cm, or inches).
- Enter the stroke and select the corresponding unit.
- Specify the total number of cylinders in your engine configuration.
- Click Calculate Displacement to compute swept volume and totals.
- Review displacement in cubic centimeters, liters, and cubic inches in the results panel.
- Use the CSV or PDF buttons to export results for documentation or comparison.
This tool is suitable for stock engines, stroker builds, and conceptual sizing studies. Always confirm final specifications with manufacturer or build documentation.
What Is Engine Displacement?
Engine displacement describes the total swept volume of all cylinders in a reciprocating engine. It is a geometric quantity derived from cylinder bore, stroke length, and cylinder count. This calculator automates the math, reducing manual mistakes when you experiment with different combinations for engines, motorcycles, or industrial machinery during design, tuning, or educational projects at any experience level.
Role of Bore and Stroke
Bore and stroke are the two core dimensions driving displacement. Bore controls cylinder diameter; stroke controls piston travel between top and bottom dead center. Small changes in either dimension quickly scale swept volume. Overboring or stroker crank upgrades are common tuning strategies, and this calculator shows their displacement impact instantly for naturally aspirated builds and forced‑induction applications.
Importance of Unit Conversion
Accurate unit handling is essential when comparing specifications from datasheets, catalogs, or workshop notes. This tool accepts millimeters, centimeters, and inches, converting everything internally to centimeters. That ensures each calculation uses consistent units and produces displacement in cubic centimeters, liters, and cubic inches without additional conversion steps or handheld conversion charts on the workshop bench for busy technicians.
Effect of Cylinder Count
Cylinder count strongly affects total capacity and engine character. A small bore and stroke multiplied across many cylinders can equal the displacement of a big‑bore, low‑cylinder configuration. This calculator highlights how inline‑four, V‑six, or V‑eight layouts reach similar capacities using different geometric design choices, sound signatures, firing orders, and packaging or weight constraints in real vehicles.
Published Specs Versus Calculated Values
Manufacturers advertise engine families by rounded displacement values, such as two liters or five liters. When you enter exact bore, stroke, and cylinder numbers from service manuals, you often obtain slightly different results. That difference arises from rounding in published specifications. This tool reveals true geometric displacement behind marketing labels and helps verify catalog claims during research.
Using Displacement in Design and Tuning
Engine builders, tuners, and students can use displacement values to size supporting components. Intake and exhaust system design, fuel injector flow rates, and turbocharger selection all depend partly on swept volume. By computing accurate displacement, you can better justify airflow targets, volumetric efficiency assumptions, realistic power expectations, and even fuel economy projections for different usage scenarios and driving styles.
Limitations of the Geometric Model
Like any geometric model, this calculator has limitations. It assumes perfectly cylindrical bores, constant stroke, and ignores combustion chamber volume and compression ratio. Real engines also experience manufacturing tolerances and wear. Use the results as a precise geometric estimate, then combine them with measured data, dyno results, and manufacturer guidance before making critical engineering decisions on important projects.
How does this calculator differ from simple online charts?
Most charts list only a few standard engines. This calculator accepts custom bore, stroke, and cylinder combinations, converts units automatically, and outputs three displacement units, allowing quick comparison of factory setups, stroker builds, and conceptual designs without searching multiple reference tables or performing manual calculations.
Can this tool calculate compression ratio or combustion chamber volume?
No. The calculator focuses strictly on geometric swept volume from bore, stroke, and cylinder count. Compression ratio requires chamber volume, piston crown shape, gasket thickness, and deck height data. You can pair displacement results with separate compression calculators for complete combustion analysis.
Why do my results differ from manufacturer advertised displacement?
Manufacturers often round displacement values for marketing simplicity, naming engines as two liters or five liters. Service manual dimensions may also be rounded. Small differences in bore or stroke multiply across cylinders. This tool reveals the underlying geometric value, which may differ slightly from brochure figures.
Is this calculator useful for motorcycle or small engine projects?
Yes. Any reciprocating piston engine using circular cylinders can be modeled, including motorcycles, karts, generators, and industrial equipment. Enter the appropriate bore, stroke, and cylinder count, choose units, and the tool returns displacement in cubic centimeters, liters, and cubic inches for consistent comparison.
Which unit system should I use for most accurate results?
Use the most precise bore and stroke measurements available, usually in millimeters from service manuals or machining notes. The calculator converts units internally, but starting with finely resolved metric dimensions minimizes rounding error and improves confidence when planning machining operations or component upgrades.
Can I export results for build logs or customer reports?
Yes. After running a calculation, use the CSV or PDF buttons to export the results table. You can attach these files to build sheets, email them to customers, or archive them alongside dyno charts and tuning notes for future reference.