Engine Displacement Calculator
Bore, stroke and cylinders to cc, litres and cubic inches.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Total displacement
- 1998.2 cc
- In litres
- 2 L
- In cubic inches
- 121.9 cu in
- Per cylinder
- 499.6 cc
- Bore/stroke character
- Square
Quick answer
Engine displacement is the volume all pistons sweep in one stroke: π ÷ 4 × bore² × stroke × number of cylinders. With bore and stroke in millimeters, divide by 1,000 for cubic centimeters. A four-cylinder with an 86 mm bore and 86 mm stroke displaces 0.7854 × 86² × 86 × 4 ÷ 1,000 ≈ 1,998 cc, sold as a 2.0-liter engine (121.9 cubic inches).
What the Engine Displacement calculator does
Enter the bore (cylinder diameter), stroke (piston travel) and number of cylinders, and this calculator gives total displacement in cc, liters and cubic inches, the volume of each cylinder, and the engine's bore-to-stroke character. It works for car, motorcycle, marine, small-engine and aircraft piston engines, both four-stroke and two-stroke.
Enter bore and stroke in millimeters. For American specs given in inches, multiply by 25.4 first – a 4.00 in bore is 101.6 mm. The length converter handles other units.
Displacement is swept volume only. It does not include the combustion chamber above the piston at top dead center, which is why compression ratio needs a separate calculation. Rotary (Wankel) engines are rated differently and do not fit this formula. To relate displacement to output, use the horsepower from torque calculator.
The formula
Displacement (cc) = π ÷ 4 × bore² × stroke × cylinders ÷ 1,000 Cubic inches = cc ÷ 16.387 Bore/stroke ratio = bore ÷ stroke
| Symbol | Meaning | Unit |
|---|---|---|
| bore | Cylinder diameter | mm |
| stroke | Distance the piston travels from bottom to top dead center (twice the crank throw) | mm |
| cylinders | Number of cylinders | count |
| π ÷ 4 | 0.7854, converts diameter squared into the area of a circle | — |
This is the volume of a cylinder (area of the bore × stroke), the standard definition of swept volume used in engineering texts such as Heywood's *Internal Combustion Engine Fundamentals* and in SAE terminology. Manufacturers round marketed sizes: 1,998 cc is sold as 2.0 L and 5,967 cc as 6.0 L. One cubic inch is exactly 16.387064 cc.
Worked examples
Classic American V8
A V8 with a 4.00 in (101.6 mm) bore and 3.62 in (92 mm) stroke.
Inputs
- Bore101.6 mm
- Stroke92 mm
- Number of cylinders8
Result
- Total displacement5967 cc
- In litres5.97 L
- In cubic inches364.1 cu in
- Per cylinder745.9 cc
- Bore/stroke characterOversquare — revs freely
About 5,967 cc or 364 cubic inches, marketed as a 6.0 L. The bore is larger than the stroke, so the engine is oversquare and can rev relatively freely for a large V8.
Long-stroke four-cylinder
An inline-four with an 81 mm bore and 87.3 mm stroke.
Inputs
- Bore81 mm
- Stroke87.3 mm
- Number of cylinders4
Result
- Total displacement1799.4 cc
- In litres1.8 L
- In cubic inches109.8 cu in
- Per cylinder449.9 cc
- Bore/stroke characterUndersquare — low-end torque
About 1,799 cc, a 1.8 L. The stroke is longer than the bore (undersquare), a layout that favors low-rpm torque and compact combustion chambers over high revs.
Single-cylinder motorcycle
A 250-class motorcycle with a 76 mm bore and 54.8 mm stroke.
Inputs
- Bore76 mm
- Stroke54.8 mm
- Number of cylinders1
Result
- Total displacement248.6 cc
- In litres0.25 L
- In cubic inches15.2 cu in
- Per cylinder248.6 cc
- Bore/stroke characterOversquare — revs freely
About 248.6 cc, under the 250 cc limit used for many licensing and racing classes. The short stroke keeps piston speed low at high rpm.
Oversquare, square and undersquare engines
The bore-to-stroke ratio shapes how an engine behaves. It is one factor among many – cam timing, intake design and tuning matter as much – but the trends are consistent.
| Type | Bore ÷ stroke | Typical character | Common uses |
|---|---|---|---|
| Undersquare (long-stroke) | Below 1.0 | Strong low-rpm torque, lower piston-speed limit on revs | Diesels, economy and truck engines |
| Square | About 1.0 | Balanced compromise | Many modern 2.0 L four-cylinders |
| Oversquare (short-stroke) | Above 1.0 | Room for bigger valves, higher rpm | Sport bikes, racing and high-revving engines |
Overboring and stroker builds
Because bore is squared, small increases add up. Overboring the V8 above by 0.030 in (to 4.030 in) raises displacement by (4.030 ÷ 4.000)² – about 1.5%, to roughly 6,057 cc. Changing the stroke scales displacement directly: a crankshaft that lengthens the stroke from 92 mm to 101.6 mm (4.00 in) adds about 10%, to roughly 6,590 cc.
To model a build, enter the new bore or stroke in the calculator. Check cylinder wall thickness with the machine shop before overboring, and remember that racing classes and some vehicle registrations are defined by displacement.
Converting between cc, liters and cubic inches
- 1 liter = 1,000 cc = 61.02 cubic inches.
- cc to cubic inches: divide by 16.387. 350 cubic inches is about 5.7 L; 302 cubic inches is about 4.9 L, though it was marketed as a 5.0.
- Single cylinder volume: the per-cylinder figure is the same as the cylinder volume calculator result for the bore and stroke, useful for checking a cylinder head's cc against the swept volume when working out compression ratio.
- Other volume units: the volume converter covers gallons, quarts and more.
How to use the Engine Displacement Calculator
- 1Find the bore and stroke in the service manual or engine spec sheet.
- 2Enter both in millimeters – multiply inches by 25.4 first.
- 3Enter the number of cylinders (V6 = 6, V8 = 8, single = 1).
- 4Read total displacement in cc, liters and cubic inches, plus per-cylinder volume and the bore/stroke character.
Frequently asked questions
How do you calculate engine displacement?
Multiply 0.7854 by the bore squared, then by the stroke and the number of cylinders. With millimeters, divide by 1,000 for cc; with inches, the result is in cubic inches directly.
How many cc is a 2.0-liter engine?
About 2,000 cc – often slightly less, such as 1,984 cc or 1,998 cc, because marketed sizes are rounded.
Does bigger displacement always mean more power?
Not always. Turbocharging, rpm and engine design matter a lot; many modern turbocharged 2.0 L engines make more power than older naturally aspirated 3.5 L engines.
How do I convert cubic inches to liters?
Multiply cubic inches by 16.387 for cc, then divide by 1,000. A 350 cubic inch engine is 5,735 cc, or 5.7 L.
Does a two-stroke engine use the same formula?
Yes. Displacement is swept volume, so the formula is identical; a two-stroke simply fires every revolution instead of every other one.
References
- Internal Combustion Engine Fundamentals (John B. Heywood) — McGraw-Hill
- Guide for the Use of the International System of Units (SI), Special Publication 811 — National Institute of Standards and Technology
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
- Report an error