About the Engine Displacement Calculator
This engine displacement calculator finds the swept volume of an engine from three measurements: cylinder bore (diameter), piston stroke and the number of cylinders. Enter the dimensions in millimetres or inches and it returns the displacement in cubic centimetres (cc), liters and cubic inches, the volume of each cylinder, and the bore-to-stroke ratio that tells you whether the engine is oversquare, square or undersquare.
It is handy for engine builders planning an overbore or stroker kit, motorcycle and small-engine owners checking a spec sheet, students learning how engines are rated, and anyone converting between the metric cc figures on bikes and the cubic inches used for classic American V8s.
Displacement is pure geometry: the area of the bore circle multiplied by the stroke, times the number of cylinders. It does not include combustion chamber volume — use the compression ratio calculator for that.
With the default inputs, the displacement is 1,998.2 cc. Change any value above to recalculate instantly.
How to use the engine displacement calculator
- 1Choose millimetres or inches.
- 2Enter the bore diameter and the stroke from the spec sheet or your measurements.
- 3Enter the number of cylinders.
- 4Read the displacement in cc, liters and cubic inches.
Formula and method
Each cylinder sweeps a cylinder-shaped volume as the piston travels from bottom dead centre to top dead centre: the circular area of the bore (π × bore² ÷ 4) multiplied by the stroke length. Multiplying by the number of cylinders gives total displacement.
With metric inputs the result is in cubic millimetres, divided by 1,000 to get cc (cm³) and by 1,000,000 for liters. With inch inputs the result is in cubic inches, converted to cc using the exact factor 1 in³ = 16.387064 cm³. The bore/stroke ratio above 1 is oversquare, below 1 undersquare.
- bore
- Cylinder diameter
- stroke
- Distance the piston travels
- cylinders
- Number of cylinders
Worked examples
Square 2.0-liter four-cylinder (86 × 86 mm)
π/4 × 86² × 86 = 499,557 mm³ per cylinder, or 499.6 cc. Four cylinders give 1,998 cc — the classic “2.0-liter” engine, about 122 cubic inches.
Small-block Chevy 350 (4.00 × 3.48 in, V8)
π/4 × 4.00² × 3.48 × 8 = 349.8 cubic inches, which is why it is called a 350. That is 5,733 cc or about 5.7 liters.
600 cc sport bike (67 × 42.5 mm, 4 cylinders)
A 67 mm bore with a short 42.5 mm stroke gives 149.8 cc per cylinder and 599 cc in total. The 1.58 bore/stroke ratio is strongly oversquare, typical of high-revving motorcycle engines.
Frequently asked questions
How do you calculate engine displacement?+
Multiply the area of one cylinder bore (π × bore² ÷ 4) by the stroke, then by the number of cylinders. Keep the units consistent: millimetres give cubic millimetres (÷ 1,000 for cc), inches give cubic inches.
How many cc are in a liter and a cubic inch?+
There are 1,000 cc in a liter, and one cubic inch equals exactly 16.387064 cc. So a 5.0-liter engine is about 305 cubic inches, and a 350 cu in engine is about 5.7 liters.
What does oversquare and undersquare mean?+
An oversquare engine has a bore larger than its stroke, which tends to allow higher rpm. An undersquare (long-stroke) engine has a stroke longer than its bore and usually favours low-rpm torque. Square engines have roughly equal bore and stroke.
How much does boring out an engine increase displacement?+
Displacement grows with the square of the bore, so small overbores add noticeable volume. For example, boring a 4.00 in V8 by 0.030 in to 4.03 in on a 3.48 in stroke raises it from about 350 to about 355 cubic inches.
Does displacement determine horsepower?+
Larger displacement lets an engine burn more air and fuel per revolution, so it generally supports more power and torque, but output also depends on rpm, cylinder head design, forced induction and tuning.