🔧 Engine Displacement Calculator
Enter the bore, stroke and number of cylinders to get the engine’s displacement in litres, cubic centimetres and cubic inches.
Displacement
2 L
1998 cc
Cubic inches
121.9 ci
Per cylinder
500 cc
Displacement = π⁄4 × bore² × stroke × cylinders. A “square” engine has bore = stroke; oversquare (bore > stroke) tends to rev higher. 1 litre = 61.02 cubic inches. 🔒 In your browser.
How the engine displacement calculator works
Each cylinder is a cylinder in the geometric sense, so its swept volume is π⁄4 × bore² × stroke. Multiply by the number of cylinders for the total displacement. The tool works in millimetres or inches and shows the result in litres, cc and cubic inches, plus the per-cylinder volume. Working it through: an 86 mm bore gives a bore area of π⁄4 × 86² ≈ 5,809 mm²; times an 86 mm stroke that is about 499,489 mm³ (499 cc) per cylinder, and four cylinders make roughly 2.0 litres. Because the bore is squared in the formula, widening the bore raises displacement far faster than lengthening the stroke by the same amount.
Bore is the cylinder’s diameter and stroke is how far the piston travels. A “square” engine has equal bore and stroke; an oversquare (bore larger than stroke) engine tends to rev higher, while an undersquare (long-stroke) design favours low-end torque.
Frequently asked questions
How do I calculate engine displacement?
Displacement = π⁄4 × bore² × stroke × number of cylinders. With bore and stroke in millimetres you get cubic millimetres; divide by 1,000 for cc. For example, an 86 mm bore and 86 mm stroke four-cylinder is about 1,998 cc (2.0 litres).
What is bore and stroke?
Bore is the diameter of each cylinder; stroke is the distance the piston travels from bottom to top. Together with the cylinder count they determine the engine’s displacement.
How many cubic inches is a 2.0 litre engine?
About 122 cubic inches, one litre is 61.02 cubic inches, so 2.0 L × 61.02 ≈ 122 ci. The tool shows litres, cc and cubic inches at once.
What is an oversquare vs undersquare engine?
Oversquare means the bore is larger than the stroke, such engines can rev higher and often make peak power up top. Undersquare (long-stroke) engines have more stroke than bore and tend to produce strong low-end torque.
Does bigger displacement mean more power?
Generally more displacement can move more air and fuel, so more potential power, but tuning, forced induction, RPM and efficiency matter enormously. A small turbocharged engine can out-power a larger naturally-aspirated one.
Why does bore affect displacement more than stroke?
The formula squares the bore (π⁄4 × bore² × stroke), so displacement grows with the square of the bore but only linearly with the stroke. Increasing the bore by 10% raises swept volume by about 21%, whereas a 10% longer stroke raises it by just 10%.
What is the difference between swept and total cylinder volume?
Swept (displacement) volume is only the space the piston sweeps through between bottom and top dead centre. Total cylinder volume also includes the clearance volume above the piston at the top, swept plus clearance, which is what the compression ratio compares against the clearance alone.