Tool Belt CalcAutomotive
Engine Displacement Calculator
Displacement from bore, stroke and cylinder count.
Result
349.8cu in
349.8 ci — 5.73 litres
- Bore
- 4 in
- Stroke
- 3.48 in
- Swept volume per cylinder
- 43.73 cu in
- Cylinders
- 8
- Total displacement
- 349.85 cu in
- In cubic centimetres
- 5733 cc
- In litres
- 5.73 L
This is swept volume — the area of the bore times the stroke, times the number of cylinders. It excludes the combustion chamber volume above the piston at top dead centre, which belongs to the compression ratio rather than to displacement.
Advertised displacements are rounded, often generously. A 5.7 litre V8 rarely measures exactly 5,700 cc, and a 350 is not exactly 350 cubic inches.
Overboring changes displacement measurably. Thirty thousandths on a four inch bore adds several cubic inches across eight cylinders.
Bore, stroke and cylinder count give swept volume in cubic inches, cubic centimetres and litres. Overboring changes it measurably — thirty thousandths across eight cylinders adds several cubic inches.
Why use this tool?
All three units
Cubic inches, cc and litres, since engines are described in all three depending on origin and era.
Per-cylinder shown
Swept volume of a single cylinder, which is what compression ratio calculations need.
Overbore aware
Enter the actual measured bore rather than the nominal one to see what a rebuild changed.
Explains what is excluded
Swept volume only — the combustion chamber belongs to compression ratio, not displacement.
How this engine displacement calculator works
Swept volume per cylinder is the area of the bore times the stroke: π times the bore radius squared, times stroke. Multiplying by cylinder count gives total displacement in cubic inches, and 16.387064 converts each cubic inch to cubic centimetres.
This is swept volume only. It excludes the combustion chamber volume above the piston at top dead centre, which is a separate quantity belonging to the compression ratio calculation.
Advertised displacements are rounded, often generously. A 5.7 litre V8 rarely measures exactly 5,700 cc, and a 350 is not exactly 350 cubic inches.
How to use it
Step 1: Measure the bore
Actual bore diameter, which on a rebuilt engine may be over nominal.
Step 2: Enter the stroke
Crankshaft stroke — unchanged unless the crank has been swapped.
Step 3: Enter cylinder count
Total cylinders, not per bank.
Step 4: Check against the badge
Expect the real figure to differ slightly from the advertised one.
Example usage
- A classic small block
- 4.00 in bore, 3.48 in stroke, 8 cylinders — 349.85 cubic inches, or 5.73 litres. Sold as a 350.
- After a 0.030 overbore
- The same engine at 4.030 in measures 355.11 cubic inches. Five cubic inches from three thousandths per cylinder wall.
- A stroker build
- 4.030 in bore with a 3.75 in stroke gives 382.66 cubic inches — the reason stroker cranks exist.
Frequently asked questions
How do I calculate engine displacement?
Bore radius squared times pi, times stroke, times the number of cylinders. Multiply cubic inches by 16.387 for cubic centimetres.
How many cc is a cubic inch?
16.387064 cc per cubic inch. A 350 cubic inch engine is about 5,735 cc, or 5.7 litres.
Does displacement include the combustion chamber?
No. Displacement is swept volume — what the piston moves through. The chamber above the piston at top dead centre belongs to the compression ratio calculation.
How much does overboring add?
More than people expect. Thirty thousandths on a four inch bore adds over five cubic inches across eight cylinders.
Why is my engine not exactly its advertised size?
Advertised displacements are rounded for marketing. A 5.7 litre is rarely 5,700 cc exactly, and a 350 is usually closer to 349.
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