Engine Displacement Calculator
Enter your bore diameter, stroke length, and number of cylinders to get total engine displacement instantly in cubic centimetres, litres, and cubic inches. Switch between metric (mm) and imperial (inches) inputs, choose how many cylinders, and see a full worked breakdown of the formula. The calculator also reverse-solves bore diameter if you already know the displacement target.
Formula
Worked example
A 4-cylinder engine with an 86 mm bore and 86 mm stroke (a square engine): V = (pi/4) x 86^2 x 86 x 4 / 1000 = 1996 cc = 2.0 L = 121.8 cu in. Bore-to-stroke ratio = 86/86 = 1.000 (perfectly square).
What is engine displacement?
Engine displacement is the total volume swept by all pistons inside the cylinders during one complete engine cycle, from bottom dead centre (BDC) to top dead centre (TDC). It is expressed in cubic centimetres (cc), litres (L), or cubic inches (cu in or CID). Displacement is the single most quoted engine specification because it correlates strongly with potential torque output: a larger swept volume can ingest more air-fuel mixture per cycle, enabling more combustion work. However, modern forced-induction engines (turbocharged or supercharged) can produce large-engine power from a small displacement by pressurising the intake charge, which is why a 2.0 L turbocharged engine can match a naturally aspirated 3.5 L in outright output.
How engine displacement is calculated
The formula is: V = (pi / 4) x bore^2 x stroke x N, where bore (D) is the cylinder internal diameter, stroke (L) is the distance the piston travels, and N is the number of cylinders. If you measure bore and stroke in millimetres, divide the result by 1000 to convert mm^3 to cc. Then divide by 1000 for litres, or by 16.387 for cubic inches. The calculator on this page does all three conversions simultaneously. It also reverse-solves the bore diameter you would need to hit a target displacement, using the rearranged formula: bore = sqrt(4 x V / (N x pi x stroke)).
Bore-to-stroke ratio: oversquare vs. undersquare vs. square
The bore-to-stroke ratio (bore divided by stroke) tells you a great deal about an engine's character. An oversquare engine (ratio above 1.0, bore wider than stroke) tends to rev freely and produce peak power at high RPM. Sports cars and high-performance motorcycle engines are typically oversquare - a wide bore allows large valves and shorter piston travel time. An undersquare engine (ratio below 1.0, stroke longer than bore) builds pressure over a longer piston travel, which produces strong low-RPM torque. Diesel engines, long-haul truck engines, and many agricultural engines are undersquare for this reason. A square engine (ratio = 1.0, bore equals stroke) is a balanced design that sits between the two extremes. Many everyday passenger car engines are close to square.
Reading the results: cc, litres, and cubic inches
All three units express the same volume: 1000 cc = 1 L = 61.02 cu in. Cubic centimetres (cc) are used widely in motorcycle and small-engine specifications. Litres are the standard for modern car engines in most of the world. Cubic inches remain common in the North American performance and vintage car community, where a 350 CID or 454 CID V8 is still described in those terms rather than 5.7 L or 7.4 L. The bore-to-stroke ratio and single-cylinder volume shown in this calculator give deeper insight than the headline displacement figure alone.
Engine displacement by application
| Application | Typical range | Example |
|---|---|---|
| Lawn mower / small tool | 50-200 cc | 140 cc Honda GX140 |
| Moped / scooter | 50-125 cc | 110 cc Honda Activa |
| Sport motorcycle | 250-1000 cc | 600 cc Yamaha R6 |
| Cruiser motorcycle | 800-2000 cc | 1800 cc Honda Gold Wing |
| Subcompact car | 600-1400 cc | 1000 cc VW Polo |
| Compact / mid-size car | 1400-2500 cc | 2000 cc Toyota Camry 2.0 |
| Full-size SUV / truck (petrol) | 3500-6200 cc | 5700 cc Toyota Tundra |
| Large V8 muscle car | 5000-8000 cc | 6200 cc Chevy Corvette Z06 |
| Heavy-duty diesel truck | 6700-15000 cc | 6700 cc Cummins 6.7 |
Typical displacement ranges for common engine types and vehicle classes.
Frequently asked questions
What does engine displacement mean?
Engine displacement is the total volume swept by all pistons in an engine during one complete cycle. A 2.0 L engine has pistons that sweep a combined 2000 cc of space per revolution. Larger displacement generally means more air-fuel mixture per cycle, which typically means more torque, though modern turbocharging can produce high output from small-displacement engines.
How do I calculate engine displacement?
Use the formula V = (pi / 4) x bore^2 x stroke x cylinders. Measure bore and stroke in mm, multiply through, and divide by 1000 to get cubic centimetres. Divide cc by 1000 for litres, or by 16.387 for cubic inches. This calculator does all three conversions simultaneously once you enter bore, stroke, and cylinder count.
What is the difference between cc and CID (cubic inches)?
1 cubic inch equals exactly 16.387 cc. So a 350 CID V8 is 350 x 16.387 = 5735 cc, or about 5.7 L. Cubic inches are traditional in the US performance and muscle car world; cc and litres are used almost everywhere else. The conversion is fixed and exact.
What does bore-to-stroke ratio tell you about an engine?
The bore-to-stroke ratio (bore divided by stroke) describes engine character. A ratio above 1.0 (oversquare) means the bore is wider than the stroke, favouring high-RPM power. A ratio below 1.0 (undersquare or long-stroke) means more stroke than bore, favouring low-RPM torque. A ratio of 1.0 is a square engine with balanced characteristics. Sports and race engines are usually oversquare; diesel and heavy-duty engines are usually undersquare.
Can I use this calculator to find the bore for a target displacement?
Yes. Switch "Solve for" to "Bore" and enter your target displacement in cc, your stroke length, and number of cylinders. The calculator rearranges the formula to bore = sqrt(4 x V / (N x pi x stroke)) and returns the required bore diameter in both mm and inches.
Does a bigger engine always mean more power?
Not necessarily. Displacement sets the upper limit of how much air-fuel mixture an engine can draw in naturally. A forced-induction (turbocharged or supercharged) engine can surpass a naturally aspirated engine of larger displacement by compressing the intake charge. Engine tune, valve timing, compression ratio, and fuel quality all affect final power output alongside displacement.